diff --git a/scripts/langindex.json b/scripts/langindex.json
index 5c2eb522717..620d2c29978 100644
--- a/scripts/langindex.json
+++ b/scripts/langindex.json
@@ -430,8 +430,12 @@
   "addon.mod_assign.numwords": "moodle",
   "addon.mod_assign.outof": "assign",
   "addon.mod_assign.overdue": "assign",
+  "addon.mod_assign.removesubmission": "assign",
+  "addon.mod_assign.removesubmissionconfirm": "assign",
+  "addon.mod_assign.removesubmissionconfirmwithtimelimit": "assign",
   "addon.mod_assign.submission": "assign",
   "addon.mod_assign.submissioneditable": "assign",
+  "addon.mod_assign.submissionempty": "assign",
   "addon.mod_assign.submissionnoteditable": "assign",
   "addon.mod_assign.submissionnotsupported": "local_moodlemobileapp",
   "addon.mod_assign.submissionslocked": "assign",
diff --git a/src/addons/mod/assign/components/index/index.ts b/src/addons/mod/assign/components/index/index.ts
index e343bbaff73..eb31d7487f4 100644
--- a/src/addons/mod/assign/components/index/index.ts
+++ b/src/addons/mod/assign/components/index/index.ts
@@ -47,6 +47,7 @@ import {
     ADDON_MOD_ASSIGN_GRADED_EVENT,
     ADDON_MOD_ASSIGN_PAGE_NAME,
     ADDON_MOD_ASSIGN_STARTED_EVENT,
+    ADDON_MOD_ASSIGN_SUBMISSION_REMOVED_EVENT,
     ADDON_MOD_ASSIGN_SUBMISSION_SAVED_EVENT,
     ADDON_MOD_ASSIGN_SUBMITTED_FOR_GRADING_EVENT,
     ADDON_MOD_ASSIGN_WARN_GROUPS_OPTIONAL,
@@ -126,6 +127,17 @@ export class AddonModAssignIndexComponent extends CoreCourseModuleMainActivityCo
             this.siteId,
         );
 
+        this.savedObserver = CoreEvents.on(
+            ADDON_MOD_ASSIGN_SUBMISSION_REMOVED_EVENT,
+            (data) => {
+                if (this.assign && data.assignmentId == this.assign.id && data.userId == this.currentUserId) {
+                    // Assignment submission removed, refresh data.
+                    this.showLoadingAndRefresh(true, false);
+                }
+            },
+            this.siteId,
+        );
+
         this.submittedObserver = CoreEvents.on(
             ADDON_MOD_ASSIGN_SUBMITTED_FOR_GRADING_EVENT,
             (data) => {
diff --git a/src/addons/mod/assign/components/submission/addon-mod-assign-submission.html b/src/addons/mod/assign/components/submission/addon-mod-assign-submission.html
index 0ee574a3fb2..ad7abb28772 100644
--- a/src/addons/mod/assign/components/submission/addon-mod-assign-submission.html
+++ b/src/addons/mod/assign/components/submission/addon-mod-assign-submission.html
@@ -167,13 +167,20 @@ <h2>{{ 'addon.mod_assign.userswhoneedtosubmit' | translate: {$a: ''} }}</h2>
                         <div class="list-item-limited-width" *ngIf="canEdit || canSubmit">
                             <ng-container *ngIf="canEdit">
                                 <ng-container *ngIf=" !unsupportedEditPlugins.length && !showErrorStatementEdit">
-                                    <!-- If has offline data, show edit. -->
-                                    <ion-button expand="block" class="ion-text-wrap" *ngIf="hasOffline" (click)="goToEdit()">
-                                        {{ 'addon.mod_assign.editsubmission' | translate }}
-                                    </ion-button>
+                                    <!-- If has offline data, show edit and remove. -->
+                                    <div *ngIf="editedOffline" class="adaptable-buttons-row">
+                                        <ion-button expand="block" class="ion-margin ion-text-wrap" (click)="goToEdit()">
+                                            {{ 'addon.mod_assign.editsubmission' | translate }}
+                                        </ion-button>
+                                        <ion-button *ngIf="isRemoveAvailable" expand="block" class="ion-margin ion-text-wrap"
+                                            (click)="remove()">
+                                            {{ 'addon.mod_assign.removesubmission' | translate }}
+                                        </ion-button>
+                                    </div>
                                     <!-- If no submission or is new, show add submission. -->
-                                    <ion-button expand="block" class="ion-text-wrap" (click)="goToEdit()" *ngIf="!hasOffline &&
-                                        (!userSubmission || !userSubmission!.status || userSubmission!.status === statusNew)">
+                                    <ion-button expand="block" class="ion-text-wrap" (click)="goToEdit()" *ngIf="!editedOffline &&
+                                            (removedOffline || !userSubmission || !userSubmission!.status ||
+                                            userSubmission!.status === statusNew)">
                                         <ng-container *ngIf="!assign?.timelimit || userSubmission?.timestarted">
                                             {{ 'addon.mod_assign.addsubmission' | translate }}
                                         </ng-container>
@@ -182,7 +189,7 @@ <h2>{{ 'addon.mod_assign.userswhoneedtosubmit' | translate: {$a: ''} }}</h2>
                                         </ng-container>
                                     </ion-button>
                                     <!-- If reopened, show addfromprevious and addnewattempt. -->
-                                    <ng-container *ngIf="!hasOffline && userSubmission?.status === statusReopened">
+                                    <ng-container *ngIf="!editedOffline && !removedOffline && userSubmission?.status === statusReopened">
                                         <ion-button *ngIf="!isPreviousAttemptEmpty" expand="block" class="ion-text-wrap"
                                             (click)="copyPrevious()">
                                             {{ 'addon.mod_assign.addnewattemptfromprevious' | translate }}
@@ -191,12 +198,18 @@ <h2>{{ 'addon.mod_assign.userswhoneedtosubmit' | translate: {$a: ''} }}</h2>
                                             {{ 'addon.mod_assign.addnewattempt' | translate }}
                                         </ion-button>
                                     </ng-container>
-                                    <!-- Else show editsubmission. -->
-                                    <ion-button expand="block" class="ion-text-wrap" *ngIf="!hasOffline && userSubmission &&
-                                        userSubmission!.status && userSubmission!.status !== statusNew &&
-                                        userSubmission!.status !== statusReopened" (click)="goToEdit()">
-                                        {{ 'addon.mod_assign.editsubmission' | translate }}
-                                    </ion-button>
+                                    <!-- Else show editsubmission and removesubmission. -->
+                                    <div *ngIf="!editedOffline && !removedOffline && userSubmission && userSubmission!.status
+                                         && userSubmission!.status !== statusNew && userSubmission!.status !== statusReopened"
+                                        class="adaptable-buttons-row">
+                                        <ion-button expand="block" class="ion-margin ion-text-wrap" (click)="goToEdit()">
+                                            {{ 'addon.mod_assign.editsubmission' | translate }}
+                                        </ion-button>
+                                        <ion-button *ngIf="isRemoveAvailable" expand="block" class="ion-margin ion-text-wrap"
+                                            (click)="remove()">
+                                            {{ 'addon.mod_assign.removesubmission' | translate }}
+                                        </ion-button>
+                                    </div>
                                 </ng-container>
                                 <ion-item class="core-danger-item ion-text-wrap"
                                     *ngIf="(unsupportedEditPlugins.length && !showErrorStatementEdit)|| showErrorStatementEdit">
diff --git a/src/addons/mod/assign/components/submission/submission.ts b/src/addons/mod/assign/components/submission/submission.ts
index f5fdd8df273..1341860e885 100644
--- a/src/addons/mod/assign/components/submission/submission.ts
+++ b/src/addons/mod/assign/components/submission/submission.ts
@@ -64,6 +64,7 @@ import {
     ADDON_MOD_ASSIGN_GRADED_EVENT,
     ADDON_MOD_ASSIGN_MANUAL_SYNCED,
     ADDON_MOD_ASSIGN_PAGE_NAME,
+    ADDON_MOD_ASSIGN_SUBMISSION_REMOVED_EVENT,
     ADDON_MOD_ASSIGN_SUBMITTED_FOR_GRADING_EVENT,
     ADDON_MOD_ASSIGN_UNLIMITED_ATTEMPTS,
 } from '../../constants';
@@ -96,8 +97,9 @@ export class AddonModAssignSubmissionComponent implements OnInit, OnDestroy, Can
     isSubmittedForGrading = false; // Whether the submission has been submitted for grading.
     acceptStatement = false; // Statement accepted (for grading).
     feedback?: AddonModAssignSubmissionFeedbackFormatted; // The feedback.
-    hasOffline = false; // Whether there is offline data.
+    editedOffline = false; // Whether the submission was added or edited in offline.
     submittedOffline = false; // Whether it was submitted in offline.
+    removedOffline = false; // Whether the submission was removed in offline.
     fromDate?: string; // Readable date when the assign started accepting submissions.
     currentAttempt = 0; // The current attempt number.
     maxAttemptsText: string; // The text for maximum attempts.
@@ -108,6 +110,7 @@ export class AddonModAssignSubmissionComponent implements OnInit, OnDestroy, Can
     membersToSubmitBlind: number[] = []; // Team members that need to submit the assignment (blindmarking).
     canSubmit = false; // Whether the user can submit for grading.
     canEdit = false; // Whether the user can edit the submission.
+    isRemoveAvailable = false; // Whether WS to remove submission is available.
     submissionStatement?: string; // The submission statement.
     showErrorStatementEdit = false; // Whether to show an error in edit due to submission statement.
     showErrorStatementSubmit = false; // Whether to show an error in submit due to submission statement.
@@ -406,6 +409,47 @@ export class AddonModAssignSubmissionComponent implements OnInit, OnDestroy, Can
         );
     }
 
+    /**
+     * Remove submisson.
+     */
+    async remove(): Promise<void> {
+        if (!this.assign || !this.userSubmission) {
+            return;
+        }
+        const message = this.assign?.timelimit ?
+            'addon.mod_assign.removesubmissionconfirmwithtimelimit' :
+            'addon.mod_assign.removesubmissionconfirm';
+        try {
+            await CoreDomUtils.showDeleteConfirm(message);
+        } catch {
+            return;
+        }
+
+        const modal = await CoreLoadings.show('core.sending', true);
+
+        try {
+            const sent = await AddonModAssign.removeSubmission(this.assign, this.userSubmission);
+
+            if (sent) {
+                CoreEvents.trigger(CoreEvents.ACTIVITY_DATA_SENT, { module: 'assign' });
+            }
+
+            CoreEvents.trigger(
+                ADDON_MOD_ASSIGN_SUBMISSION_REMOVED_EVENT,
+                {
+                    assignmentId: this.assign.id,
+                    submissionId: this.userSubmission.id,
+                    userId: this.currentUserId,
+                },
+                CoreSites.getCurrentSiteId(),
+            );
+        } catch (error) {
+            CoreDomUtils.showErrorModalDefault(error, 'Error removing submission.');
+        } finally {
+            modal.dismiss();
+        }
+    }
+
     /**
      * Check if there's data to save (grade).
      *
@@ -633,13 +677,14 @@ export class AddonModAssignSubmissionComponent implements OnInit, OnDestroy, Can
         try {
             const submission = await AddonModAssignOffline.getSubmission(this.assign.id, this.submitId);
 
-            this.hasOffline = submission && submission.plugindata && Object.keys(submission.plugindata).length > 0;
-
-            this.submittedOffline = !!submission?.submitted;
+            this.removedOffline = submission && Object.keys(submission.plugindata).length == 0;
+            this.editedOffline = submission && !this.removedOffline;
+            this.submittedOffline = !!submission?.submitted && !this.removedOffline;
         } catch (error) {
             // No offline data found.
-            this.hasOffline = false;
+            this.editedOffline = false;
             this.submittedOffline = false;
+            this.removedOffline = false;
         }
     }
 
@@ -821,14 +866,14 @@ export class AddonModAssignSubmissionComponent implements OnInit, OnDestroy, Can
             return;
         }
 
-        if (this.hasOffline || this.submittedOffline) {
-            // Offline data.
+        if (this.editedOffline || this.submittedOffline) {
+            // Added, edited or submitted offline.
             this.statusTranslated = Translate.instant('core.notsent');
             this.statusColor = CoreIonicColorNames.WARNING;
         } else if (!this.assign.teamsubmission) {
 
             // Single submission.
-            if (this.userSubmission && this.userSubmission.status != this.statusNew) {
+            if (this.userSubmission && this.userSubmission.status != this.statusNew && !this.removedOffline) {
                 this.statusTranslated = Translate.instant('addon.mod_assign.submissionstatus_' + this.userSubmission.status);
                 this.statusColor = AddonModAssign.getSubmissionStatusColor(this.userSubmission.status);
             } else {
@@ -844,10 +889,10 @@ export class AddonModAssignSubmissionComponent implements OnInit, OnDestroy, Can
         } else {
 
             // Team submission.
-            if (!status.lastattempt?.submissiongroup && this.assign.preventsubmissionnotingroup) {
+            if (!status.lastattempt?.submissiongroup && this.assign.preventsubmissionnotingroup && !this.removedOffline) {
                 this.statusTranslated = Translate.instant('addon.mod_assign.nosubmission');
                 this.statusColor = AddonModAssign.getSubmissionStatusColor(AddonModAssignSubmissionStatusValues.NO_SUBMISSION);
-            } else if (this.userSubmission && this.userSubmission.status != this.statusNew) {
+            } else if (this.userSubmission && this.userSubmission.status != this.statusNew && !this.removedOffline) {
                 this.statusTranslated = Translate.instant('addon.mod_assign.submissionstatus_' + this.userSubmission.status);
                 this.statusColor = AddonModAssign.getSubmissionStatusColor(this.userSubmission.status);
             } else {
@@ -907,7 +952,7 @@ export class AddonModAssignSubmissionComponent implements OnInit, OnDestroy, Can
                     this.courseId,
                     acceptStatement,
                     this.userSubmission.timemodified,
-                    this.hasOffline,
+                    this.editedOffline,
                 );
 
                 // Submitted, trigger event.
@@ -1142,11 +1187,12 @@ export class AddonModAssignSubmissionComponent implements OnInit, OnDestroy, Can
             this.assign.requiresubmissionstatement = 0;
         }
 
-        this.canSubmit = !this.isSubmittedForGrading && !this.submittedOffline && (lastAttempt.cansubmit ||
-            (this.hasOffline && AddonModAssign.canSubmitOffline(this.assign, submissionStatus)));
+        this.canSubmit = !this.isSubmittedForGrading && !this.submittedOffline && !this.removedOffline &&
+            (lastAttempt.cansubmit || (this.editedOffline && AddonModAssign.canSubmitOffline(this.assign, submissionStatus)));
 
         this.canEdit = !this.isSubmittedForGrading && lastAttempt.canedit &&
             (!this.submittedOffline || !this.assign.submissiondrafts);
+        this.isRemoveAvailable = AddonModAssign.isRemoveSubmissionAvailable();
 
         // Get submission statement if needed.
         if (this.assign.requiresubmissionstatement && this.assign.submissiondrafts && this.submitId == this.currentUserId) {
diff --git a/src/addons/mod/assign/constants.ts b/src/addons/mod/assign/constants.ts
index 52797e8540c..914a1a99805 100644
--- a/src/addons/mod/assign/constants.ts
+++ b/src/addons/mod/assign/constants.ts
@@ -25,6 +25,7 @@ export const ADDON_MOD_ASSIGN_WARN_GROUPS_OPTIONAL = 'warnoptional';
 
 // Events.
 export const ADDON_MOD_ASSIGN_SUBMISSION_SAVED_EVENT = 'addon_mod_assign_submission_saved';
+export const ADDON_MOD_ASSIGN_SUBMISSION_REMOVED_EVENT = 'addon_mod_assign_submission_removed';
 export const ADDON_MOD_ASSIGN_SUBMITTED_FOR_GRADING_EVENT = 'addon_mod_assign_submitted_for_grading';
 export const ADDON_MOD_ASSIGN_GRADED_EVENT = 'addon_mod_assign_graded';
 export const ADDON_MOD_ASSIGN_STARTED_EVENT = 'addon_mod_assign_started';
diff --git a/src/addons/mod/assign/lang.json b/src/addons/mod/assign/lang.json
index 6806d8ad031..e1e2cf0aa65 100644
--- a/src/addons/mod/assign/lang.json
+++ b/src/addons/mod/assign/lang.json
@@ -82,8 +82,12 @@
     "numwords": "{{$a}} words",
     "outof": "{{$a.current}} out of {{$a.total}}",
     "overdue": "Assignment is overdue by: {{$a}}",
+    "removesubmission": "Remove submission",
+    "removesubmissionconfirm": "Are you sure you want to remove your submission?",
+    "removesubmissionconfirmwithtimelimit": "Are you sure you want to remove your submission? Please note that this will not reset your time limit.",
     "submission": "Submission",
     "submissioneditable": "Student can edit this submission",
+    "submissionempty": "Nothing was submitted",
     "submissionnoteditable": "Student cannot edit this submission",
     "submissionnotsupported": "This submission is not supported by the app and may not contain all the information.",
     "submissionslocked": "This assignment is not accepting submissions",
diff --git a/src/addons/mod/assign/pages/edit/edit.ts b/src/addons/mod/assign/pages/edit/edit.ts
index d11712cd6a9..6b6154c4378 100644
--- a/src/addons/mod/assign/pages/edit/edit.ts
+++ b/src/addons/mod/assign/pages/edit/edit.ts
@@ -231,15 +231,8 @@ export class AddonModAssignEditPage implements OnInit, OnDestroy, CanLeave {
                 this.timeLimitEndTime = 0;
             }
 
-            try {
-                // Check if there's any offline data for this submission.
-                const offlineData = await AddonModAssignOffline.getSubmission(this.assign.id, this.userId);
-
-                this.hasOffline = offlineData?.plugindata && Object.keys(offlineData.plugindata).length > 0;
-            } catch {
-                // No offline data found.
-                this.hasOffline = false;
-            }
+            // Check if there's any offline data for this submission.
+            this.hasOffline = await CoreUtils.promiseWorks(AddonModAssignOffline.getSubmission(this.assign.id, this.userId));
 
             CoreAnalytics.logEvent({
                 type: CoreAnalyticsEventType.VIEW_ITEM,
@@ -398,6 +391,10 @@ export class AddonModAssignEditPage implements OnInit, OnDestroy, CanLeave {
             throw Translate.instant('addon.mod_assign.acceptsubmissionstatement');
         }
 
+        if (AddonModAssignHelper.isSubmissionEmptyForEdit(this.assign!, this.userSubmission!, inputData)) {
+            throw Translate.instant('addon.mod_assign.submissionempty');
+        }
+
         let modal = await CoreLoadings.show();
         let size = -1;
 
diff --git a/src/addons/mod/assign/services/assign-helper.ts b/src/addons/mod/assign/services/assign-helper.ts
index c191c8013dd..a816ecab6de 100644
--- a/src/addons/mod/assign/services/assign-helper.ts
+++ b/src/addons/mod/assign/services/assign-helper.ts
@@ -81,6 +81,12 @@ export class AddonModAssignHelperProvider {
             return true;
         }
 
+        if (await CoreUtils.promiseWorks(AddonModAssignOffline.getSubmission(assign.id, submission.userid))) {
+            // Submission was saved or deleted offline, allow editing it or creating a new one.
+            return true;
+        }
+
+        // Submission was created online, check if plugins allow editing it.
         let canEdit = true;
 
         const promises = submission.plugins
@@ -237,6 +243,31 @@ export class AddonModAssignHelperProvider {
         return true;
     }
 
+    /**
+     * Check whether the edited submission has no content.
+     *
+     * @param assign Assignment object.
+     * @param submission Submission to inspect.
+     * @param inputData Data entered in the submission form.
+     * @returns Whether the submission is empty.
+     */
+    isSubmissionEmptyForEdit(
+        assign: AddonModAssignAssign,
+        submission: AddonModAssignSubmission,
+        inputData: CoreFormFields,
+    ): boolean {
+        const anyNotEmpty = submission.plugins?.some((plugin) =>
+            !AddonModAssignSubmissionDelegate.isPluginEmptyForEdit(assign, plugin, inputData));
+
+        // If any plugin is not empty, we consider that the submission is not empty either.
+        if (anyNotEmpty) {
+            return false;
+        }
+
+        // If all the plugins were empty (or there were no plugins), we consider the submission to be empty.
+        return true;
+    }
+
     /**
      * List the participants for a single assignment, with some summary info about their submissions.
      *
@@ -467,7 +498,7 @@ export class AddonModAssignHelperProvider {
             submission.manyGroups = !!participant.groups && participant.groups.length > 1;
             submission.noGroups = !!participant.groups && participant.groups.length == 0;
             if (participant.groupname) {
-                submission.groupid = participant.groupid;
+                submission.groupid = participant.groupid ?? 0;
                 submission.groupname = participant.groupname;
             }
 
@@ -724,18 +755,15 @@ export const AddonModAssignHelper = makeSingleton(AddonModAssignHelperProvider);
 /**
  * Assign submission with some calculated data.
  */
-export type AddonModAssignSubmissionFormatted =
-    Omit<AddonModAssignSubmission, 'userid'|'groupid'> & {
-        userid?: number; // Student id.
-        groupid?: number; // Group id.
-        blindid?: number; // Calculated in the app. Blindid of the user that did the submission.
-        submitid?: number; // Calculated in the app. Userid or blindid of the user that did the submission.
-        userfullname?: string; // Calculated in the app. Full name of the user that did the submission.
-        userprofileimageurl?: string; // Calculated in the app. Avatar of the user that did the submission.
-        manyGroups?: boolean; // Calculated in the app. Whether the user belongs to more than 1 group.
-        noGroups?: boolean; // Calculated in the app. Whether the user doesn't belong to any group.
-        groupname?: string; // Calculated in the app. Name of the group the submission belongs to.
-    };
+export interface AddonModAssignSubmissionFormatted extends AddonModAssignSubmission {
+    blindid?: number; // Calculated in the app. Blindid of the user that did the submission.
+    submitid?: number; // Calculated in the app. Userid or blindid of the user that did the submission.
+    userfullname?: string; // Calculated in the app. Full name of the user that did the submission.
+    userprofileimageurl?: string; // Calculated in the app. Avatar of the user that did the submission.
+    manyGroups?: boolean; // Calculated in the app. Whether the user belongs to more than 1 group.
+    noGroups?: boolean; // Calculated in the app. Whether the user doesn't belong to any group.
+    groupname?: string; // Calculated in the app. Name of the group the submission belongs to.
+}
 
 /**
  * Assignment plugin config.
diff --git a/src/addons/mod/assign/services/assign-sync.ts b/src/addons/mod/assign/services/assign-sync.ts
index 19137968e20..063e3f1cdb3 100644
--- a/src/addons/mod/assign/services/assign-sync.ts
+++ b/src/addons/mod/assign/services/assign-sync.ts
@@ -331,27 +331,29 @@ export class AddonModAssignSyncProvider extends CoreCourseActivitySyncBaseProvid
         }
 
         try {
-            if (submission?.plugins) {
-                // Prepare plugins data.
-                await Promise.all(submission.plugins.map((plugin) =>
-                    AddonModAssignSubmissionDelegate.preparePluginSyncData(
-                        assign,
-                        submission,
-                        plugin,
-                        offlineData,
-                        pluginData,
-                        siteId,
-                    )));
-            }
+            if (Object.keys(offlineData.plugindata).length == 0) {
+                await AddonModAssign.removeSubmissionOnline(assign.id, offlineData.userid, siteId);
+            } else {
+                if (submission?.plugins) {
+                    // Prepare plugins data.
+                    await Promise.all(submission.plugins.map((plugin) =>
+                        AddonModAssignSubmissionDelegate.preparePluginSyncData(
+                            assign,
+                            submission,
+                            plugin,
+                            offlineData,
+                            pluginData,
+                            siteId,
+                        )));
+                }
 
-            // Now save the submission.
-            if (Object.keys(pluginData).length > 0) {
+                // Now save the submission.
                 await AddonModAssign.saveSubmissionOnline(assign.id, pluginData, siteId);
-            }
 
-            if (assign.submissiondrafts && offlineData.submitted) {
-                // The user submitted the assign manually. Submit it for grading.
-                await AddonModAssign.submitForGradingOnline(assign.id, !!offlineData.submissionstatement, siteId);
+                if (assign.submissiondrafts && offlineData.submitted) {
+                    // The user submitted the assign manually. Submit it for grading.
+                    await AddonModAssign.submitForGradingOnline(assign.id, !!offlineData.submissionstatement, siteId);
+                }
             }
 
             // Submission data sent, update cached data. No need to block the user for this.
diff --git a/src/addons/mod/assign/services/assign.ts b/src/addons/mod/assign/services/assign.ts
index 976ca8abed3..a4d5216cd36 100644
--- a/src/addons/mod/assign/services/assign.ts
+++ b/src/addons/mod/assign/services/assign.ts
@@ -42,6 +42,7 @@ import {
     ADDON_MOD_ASSIGN_GRADED_EVENT,
     ADDON_MOD_ASSIGN_MANUAL_SYNCED,
     ADDON_MOD_ASSIGN_STARTED_EVENT,
+    ADDON_MOD_ASSIGN_SUBMISSION_REMOVED_EVENT,
     ADDON_MOD_ASSIGN_SUBMISSION_SAVED_EVENT,
     ADDON_MOD_ASSIGN_SUBMITTED_FOR_GRADING_EVENT,
 } from '../constants';
@@ -55,6 +56,7 @@ declare module '@singletons/events' {
      */
     export interface CoreEventsData {
         [ADDON_MOD_ASSIGN_SUBMISSION_SAVED_EVENT]: AddonModAssignSubmissionSavedEventData;
+        [ADDON_MOD_ASSIGN_SUBMISSION_REMOVED_EVENT]: AddonModAssignSubmissionRemovedEventData;
         [ADDON_MOD_ASSIGN_SUBMITTED_FOR_GRADING_EVENT]: AddonModAssignSubmittedForGradingEventData;
         [ADDON_MOD_ASSIGN_GRADED_EVENT]: AddonModAssignGradedEventData;
         [ADDON_MOD_ASSIGN_STARTED_EVENT]: AddonModAssignStartedEventData;
@@ -1314,6 +1316,125 @@ export class AddonModAssignProvider {
         }
     }
 
+    /**
+     * Remove the assignment submission of a user.
+     *
+     * @param assign Assign.
+     * @param submission Last online submission.
+     * @param siteId Site ID. If not defined, current site.
+     * @returns Promise resolved with true if sent to server, resolved with false if stored in offline.
+     * @since 4.5
+     */
+    async removeSubmission(
+        assign: AddonModAssignAssign,
+        submission: AddonModAssignSubmission,
+        siteId?: string,
+    ): Promise<boolean> {
+        siteId = siteId || CoreSites.getCurrentSiteId();
+
+        // Function to store the submission to be synchronized later.
+        const storeOffline = async (): Promise<boolean> => {
+            await AddonModAssignOffline.saveSubmission(
+                assign.id,
+                assign.course,
+                {},
+                submission.timemodified,
+                !!assign.submissiondrafts,
+                submission.userid,
+                siteId,
+            );
+
+            return false;
+        };
+
+        if (submission.status === AddonModAssignSubmissionStatusValues.NEW ||
+                submission.status == AddonModAssignSubmissionStatusValues.REOPENED) {
+            // The submission was created offline and not synced, just delete the offline submission.
+            await AddonModAssignOffline.deleteSubmission(assign.id, submission.userid, siteId);
+
+            return false;
+        }
+
+        if (!CoreNetwork.isOnline()) {
+            // App is offline, store the action.
+            return storeOffline();
+        }
+
+        try {
+            // If there's an offline submission, discard it first.
+            const offlineData = await AddonModAssignOffline.getSubmission(assign.id, submission.userid, siteId);
+
+            if (offlineData) {
+                if (submission.plugins) {
+                    // Delete all plugin data.
+                    await Promise.all(submission.plugins.map((plugin) =>
+                        AddonModAssignSubmissionDelegate.deletePluginOfflineData(
+                            assign,
+                            submission,
+                            plugin,
+                            offlineData,
+                            siteId,
+                        )));
+                }
+
+                await AddonModAssignOffline.deleteSubmission(assign.id, submission.userid, siteId);
+            }
+
+            await this.removeSubmissionOnline(assign.id, submission.userid, siteId);
+
+            return true;
+        } catch (error) {
+            if (error && !CoreUtils.isWebServiceError(error)) {
+                // Couldn't connect to server, store in offline.
+                return storeOffline();
+            } else {
+                // The WebService has thrown an error or offline not supported, reject.
+                throw error;
+            }
+        }
+    }
+
+    /**
+     * Remove the assignment submission of a user.
+     *
+     * @param assignId Assign ID.
+     * @param userId User ID. If not defined, current user.
+     * @param siteId Site ID. If not defined, current site.
+     * @returns Promise resolved when submitted, rejected otherwise.
+     * @since 4.5
+     */
+    async removeSubmissionOnline(assignId: number, userId?: number, siteId?: string): Promise<void> {
+        const site = await CoreSites.getSite(siteId);
+        userId = userId || site.getUserId();
+
+        const params: AddonModAssignRemoveSubmissionWSParams = {
+            assignid: assignId,
+            userid: userId,
+        };
+        const result = await site.write<AddonModAssignRemoveSubmissionWSResponse>('mod_assign_remove_submission', params);
+
+        if (!result.status) {
+            if (result.warnings?.length) {
+                throw new CoreWSError(result.warnings[0]);
+            } else {
+                throw new CoreError('Error removing assignment submission.');
+            }
+        }
+    }
+
+    /**
+     * Returns whether or not remove submission WS available or not.
+     *
+     * @param site Site. If not defined, current site.
+     * @returns If WS is available.
+     * @since 4.5
+     */
+    isRemoveSubmissionAvailable(site?: CoreSite): boolean {
+        site = site ?? CoreSites.getRequiredCurrentSite();
+
+        return site.wsAvailable('mod_assign_remove_submission');
+    }
+
 }
 export const AddonModAssign = makeSingleton(AddonModAssignProvider);
 
@@ -1755,6 +1876,22 @@ type AddonModAssignStartSubmissionWSParams = {
     assignid: number; // Assignment instance id.
 };
 
+/**
+ * Params of mod_assign_remove_submission WS.
+ */
+type AddonModAssignRemoveSubmissionWSParams = {
+    userid: number; // User id.
+    assignid: number; // Assignment instance id.
+};
+
+/**
+ * Data returned by mod_assign_remove_submission WS.
+ */
+export type AddonModAssignRemoveSubmissionWSResponse = {
+    status: boolean;
+    warnings?: CoreWSExternalWarning[];
+};
+
 /**
  * Data returned by mod_assign_start_submission WS.
  *
@@ -1784,6 +1921,11 @@ export type AddonModAssignSubmittedForGradingEventData = {
  */
 export type AddonModAssignSubmissionSavedEventData = AddonModAssignSubmittedForGradingEventData;
 
+/**
+ * Data sent by SUBMISSION_REMOVED_EVENT event.
+ */
+export type AddonModAssignSubmissionRemovedEventData = AddonModAssignSubmittedForGradingEventData;
+
 /**
  * Data sent by GRADED_EVENT event.
  */
diff --git a/src/addons/mod/assign/services/handlers/default-submission.ts b/src/addons/mod/assign/services/handlers/default-submission.ts
index e78516b5731..2365c122e54 100644
--- a/src/addons/mod/assign/services/handlers/default-submission.ts
+++ b/src/addons/mod/assign/services/handlers/default-submission.ts
@@ -50,6 +50,17 @@ export class AddonModAssignDefaultSubmissionHandler implements AddonModAssignSub
         return true;
     }
 
+    /**
+     * @inheritdoc
+     */
+   isEmptyForEdit(
+       assign: AddonModAssignAssign, // eslint-disable-line @typescript-eslint/no-unused-vars
+       plugin: AddonModAssignPlugin, // eslint-disable-line @typescript-eslint/no-unused-vars
+       inputData: CoreFormFields, // eslint-disable-line @typescript-eslint/no-unused-vars
+    ): boolean {
+        return true;
+    }
+
     /**
      * @inheritdoc
      */
diff --git a/src/addons/mod/assign/services/submission-delegate.ts b/src/addons/mod/assign/services/submission-delegate.ts
index 872fe75f1ac..f50e718fc10 100644
--- a/src/addons/mod/assign/services/submission-delegate.ts
+++ b/src/addons/mod/assign/services/submission-delegate.ts
@@ -62,6 +62,20 @@ export interface AddonModAssignSubmissionHandler extends CoreDelegateHandler {
         plugin: AddonModAssignPlugin,
     ): boolean;
 
+    /**
+     * Check if a plugin has no data in the edit form.
+     *
+     * @param assign The assignment.
+     * @param plugin The plugin object.
+     * @param inputData Data entered by the user for the submission.
+     * @returns Whether the plugin is empty.
+     */
+    isEmptyForEdit?(
+        assign: AddonModAssignAssign,
+        plugin: AddonModAssignPlugin,
+        inputData: CoreFormFields,
+    ): boolean;
+
     /**
      * Should clear temporary data for a cancelled submission.
      *
@@ -502,6 +516,22 @@ export class AddonModAssignSubmissionDelegateService extends CoreDelegate<AddonM
         return this.executeFunctionOnEnabled(plugin.type, 'isEmpty', [assign, plugin]);
     }
 
+    /**
+     * Check if a plugin has no data in the edit form
+     *
+     * @param assign The assignment.
+     * @param plugin The plugin object.
+     * @param inputData Data entered in the submission form.
+     * @returns Whether the plugin is empty.
+     */
+    isPluginEmptyForEdit(
+        assign: AddonModAssignAssign,
+        plugin: AddonModAssignPlugin,
+        inputData: CoreFormFields,
+    ): boolean | undefined {
+        return this.executeFunctionOnEnabled(plugin.type, 'isEmptyForEdit', [assign, plugin, inputData]);
+    }
+
     /**
      * Prefetch any required data for a submission plugin.
      *
diff --git a/src/addons/mod/assign/submission/file/component/file.ts b/src/addons/mod/assign/submission/file/component/file.ts
index 588c7e9ee96..e142c842f5c 100644
--- a/src/addons/mod/assign/submission/file/component/file.ts
+++ b/src/addons/mod/assign/submission/file/component/file.ts
@@ -54,28 +54,31 @@ export class AddonModAssignSubmissionFileComponent extends AddonModAssignSubmiss
             : undefined;
 
         // Get the offline data.
-        const filesData = await CoreUtils.ignoreErrors(
+        const offlineData = await CoreUtils.ignoreErrors(
             AddonModAssignOffline.getSubmission(this.assign.id),
             undefined,
         );
 
         try {
-            if (filesData && filesData.plugindata && filesData.plugindata.files_filemanager) {
-                const offlineDataFiles = <CoreFileUploaderStoreFilesResult>filesData.plugindata.files_filemanager;
-                // It has offline data.
-                let offlineFiles: FileEntry[] = [];
-                if (offlineDataFiles.offline) {
-                    offlineFiles = <FileEntry[]>await CoreUtils.ignoreErrors(
-                        AddonModAssignHelper.getStoredSubmissionFiles(
-                            this.assign.id,
-                            AddonModAssignSubmissionFileHandlerService.FOLDER_NAME,
-                        ),
-                        [],
-                    );
-                }
+            if (offlineData) {
+                // Offline submission, get files if submission is not removed.
+                if (offlineData.plugindata.files_filemanager) {
+                    const offlineDataFiles = <CoreFileUploaderStoreFilesResult>offlineData.plugindata.files_filemanager;
+                    // It has offline data.
+                    let offlineFiles: FileEntry[] = [];
+                    if (offlineDataFiles.offline) {
+                        offlineFiles = <FileEntry[]>await CoreUtils.ignoreErrors(
+                            AddonModAssignHelper.getStoredSubmissionFiles(
+                                this.assign.id,
+                                AddonModAssignSubmissionFileHandlerService.FOLDER_NAME,
+                            ),
+                            [],
+                        );
+                    }
 
-                this.files = offlineDataFiles.online || [];
-                this.files = this.files.concat(offlineFiles);
+                    this.files = offlineDataFiles.online || [];
+                    this.files = this.files.concat(offlineFiles);
+                }
             } else {
                 // No offline data, get the online files.
                 this.files = AddonModAssign.getSubmissionPluginAttachments(this.plugin);
diff --git a/src/addons/mod/assign/submission/file/services/handler.ts b/src/addons/mod/assign/submission/file/services/handler.ts
index 595572d4d7e..838c26a1eeb 100644
--- a/src/addons/mod/assign/submission/file/services/handler.ts
+++ b/src/addons/mod/assign/submission/file/services/handler.ts
@@ -61,6 +61,15 @@ export class AddonModAssignSubmissionFileHandlerService implements AddonModAssig
         return files.length === 0;
     }
 
+    /**
+     * @inheritdoc
+     */
+    isEmptyForEdit(assign: AddonModAssignAssign): boolean {
+        const currentFiles = CoreFileSession.getFiles(ADDON_MOD_ASSIGN_COMPONENT, assign.id);
+
+        return currentFiles.length == 0;
+     }
+
     /**
      * @inheritdoc
      */
diff --git a/src/addons/mod/assign/submission/onlinetext/component/onlinetext.ts b/src/addons/mod/assign/submission/onlinetext/component/onlinetext.ts
index 47760672d7f..04447b4d330 100644
--- a/src/addons/mod/assign/submission/onlinetext/component/onlinetext.ts
+++ b/src/addons/mod/assign/submission/onlinetext/component/onlinetext.ts
@@ -69,8 +69,11 @@ export class AddonModAssignSubmissionOnlineTextComponent extends AddonModAssignS
         this.wordLimit = parseInt(this.configs?.wordlimit || '0');
 
         try {
-            if (offlineData && offlineData.plugindata && offlineData.plugindata.onlinetext_editor) {
-                this.text = (<AddonModAssignSubmissionOnlineTextPluginData>offlineData.plugindata).onlinetext_editor.text;
+            if (offlineData && offlineData.plugindata) {
+                // Offline submission, get text if submission is not removed.
+                if (offlineData.plugindata.onlinetext_editor) {
+                    this.text = (<AddonModAssignSubmissionOnlineTextPluginData>offlineData.plugindata).onlinetext_editor.text;
+                }
             } else {
                 // No offline data found, return online text.
                 this.text = AddonModAssign.getSubmissionPluginText(this.plugin);
diff --git a/src/addons/mod/assign/submission/onlinetext/services/handler.ts b/src/addons/mod/assign/submission/onlinetext/services/handler.ts
index ac88ded41bb..73a5b318d94 100644
--- a/src/addons/mod/assign/submission/onlinetext/services/handler.ts
+++ b/src/addons/mod/assign/submission/onlinetext/services/handler.ts
@@ -58,6 +58,29 @@ export class AddonModAssignSubmissionOnlineTextHandlerService implements AddonMo
         return text.trim().length === 0;
     }
 
+    /**
+     * @inheritdoc
+     */
+    isEmptyForEdit(
+        assign: AddonModAssignAssign,
+        plugin: AddonModAssignPlugin,
+        inputData: AddonModAssignSubmissionOnlineTextData,
+     ): boolean {
+        const text = this.getTextToSubmit(plugin, inputData);
+
+        if (CoreText.countWords(text) > 0) {
+            return false;
+        }
+
+        // Check if the online text submission contains video, audio or image elements
+        // that can be ignored and stripped by count_words().
+        if (/<\s*((video|audio)[^>]*>(.*?)<\s*\/\s*(video|audio)>)|(img[^>]*>)/.test(text)) {
+            return false;
+        }
+
+        return true;
+     }
+
     /**
      * @inheritdoc
      */
diff --git a/src/addons/mod/assign/tests/behat/basic_usage.feature b/src/addons/mod/assign/tests/behat/basic_usage.feature
index 94bce17794b..9cbf92c1702 100755
--- a/src/addons/mod/assign/tests/behat/basic_usage.feature
+++ b/src/addons/mod/assign/tests/behat/basic_usage.feature
@@ -120,6 +120,17 @@ Feature: Test basic usage of assignment activity in app
     Then I should find "Online text submissions" in the app
     And I should find "Submission test 2nd attempt" in the app
 
+  @lms_from4.5
+  Scenario: Remove submission (online text)
+    Given I entered the assign activity "assignment1" on course "Course 1" as "student1" in the app
+    And I press "Add submission" in the app
+    And I set the field "Online text submissions" to "Submission test" in the app
+    And I press "Save" in the app
+
+    When I press "Remove submission" in the app
+    And I press "DELETE" in the app
+    Then I should find "No attempt" in the app
+
   Scenario: Add submission offline (online text) & Submit for grading offline & Sync submissions
     Given I entered the assign activity "assignment1" on course "Course 1" as "student1" in the app
     When I press "Add submission" in the app
@@ -164,3 +175,73 @@ Feature: Test basic usage of assignment activity in app
     Then I should find "Submitted for grading" in the app
     And I should find "Submission test edited offline" in the app
     But I should not find "This Assignment has offline data to be synchronised." in the app
+
+  @lms_from4.5
+  Scenario: Remove submission offline and syncrhonize it
+    Given I entered the assign activity "assignment1" on course "Course 1" as "student1" in the app
+    And I press "Add submission" in the app
+    And I set the field "Online text submissions" to "Submission test" in the app
+    And I press "Save" in the app
+    Then I should find "Draft (not submitted)" in the app
+
+    # Remove submission added online.
+    When I switch network connection to offline
+    And I press "Remove submission" in the app
+    And I press "DELETE" in the app
+    Then I should find "No attempt" in the app
+    And I should find "This Assignment has offline data to be synchronised." in the app
+
+    # Synchronize submission removal.
+    When I switch network connection to wifi
+    And I press the back button in the app
+    And I press "assignment1" in the app
+    Then I should find "No attempt" in the app
+    But I should not find "This Assignment has offline data to be synchronised." in the app
+
+    # Remove submission added offline (while offline)
+    Given I press "Add submission" in the app
+    And I set the field "Online text submissions" to "Submission test offline" in the app
+    And I switch network connection to offline
+    And I press "Save" in the app
+
+    When I press "Remove submission" in the app
+    And I press "DELETE" in the app
+    Then I should find "No attempt" in the app
+    But I should not find "This Assignment has offline data to be synchronised." in the app
+
+    # Remove submission added offline (while online before synchronising)
+    Given I press "Add submission" in the app
+    And I set the field "Online text submissions" to "Submission test offline" in the app
+    And I switch network connection to offline
+    And I press "Save" in the app
+    And I switch network connection to wifi
+
+    When I press "Remove submission" in the app
+    And I press "DELETE" in the app
+    Then I should find "No attempt" in the app
+    But I should not find "This Assignment has offline data to be synchronised." in the app
+
+  @lms_from4.5
+  Scenario: Add submission offline after removing a submission offline
+    Given I entered the assign activity "assignment1" on course "Course 1" as "student1" in the app
+    When I press "Add submission" in the app
+    And I set the field "Online text submissions" to "Submission test online" in the app
+    And I press "Save" in the app
+    And I switch network connection to offline
+    And I press "Remove submission" in the app
+    And I press "DELETE" in the app
+    Then I should find "This Assignment has offline data to be synchronised." in the app
+    And I should find "No attempt" in the app
+
+    When I press "Add submission" in the app
+    And I set the field "Online text submissions" to "Submission test offline" in the app
+    And I press "Save" in the app
+    And I press "OK" in the app
+    Then I should find "This Assignment has offline data to be synchronised." in the app
+    And I should find "Submission test offline" in the app
+
+    When I switch network connection to wifi
+    And I go back in the app
+    And I press "assignment1" in the app
+    Then I should find "Submission test offline" in the app
+    But I should not find "This Assignment has offline data to be synchronised." in the app