diff --git a/packages/backend/src/core/ChatService.ts b/packages/backend/src/core/ChatService.ts
index 334a798483..84062e5e25 100644
--- a/packages/backend/src/core/ChatService.ts
+++ b/packages/backend/src/core/ChatService.ts
@@ -255,20 +255,27 @@ export class ChatService {
 		await redisPipeline.exec();
 	}
 
+	@bindThis
+	public findMyMessageById(userId: MiUser['id'], messageId: MiChatMessage['id']) {
+		return this.chatMessagesRepository.findOneBy({ id: messageId, fromUserId: userId });
+	}
+
 	@bindThis
 	public async deleteMessage(message: MiChatMessage) {
 		await this.chatMessagesRepository.delete(message.id);
 
 		if (message.toUserId) {
-			const fromUser = await this.usersRepository.findOneByOrFail({ id: message.fromUserId });
-			const toUser = await this.usersRepository.findOneByOrFail({ id: message.toUserId });
+			const [fromUser, toUser] = await Promise.all([
+				this.usersRepository.findOneByOrFail({ id: message.fromUserId }),
+				this.usersRepository.findOneByOrFail({ id: message.toUserId }),
+			]);
 
 			if (this.userEntityService.isLocalUser(fromUser)) this.globalEventService.publishChatStream(message.fromUserId, message.toUserId, 'deleted', message.id);
 			if (this.userEntityService.isLocalUser(toUser)) this.globalEventService.publishChatStream(message.toUserId, message.fromUserId, 'deleted', message.id);
 
 			if (this.userEntityService.isLocalUser(fromUser) && this.userEntityService.isRemoteUser(toUser)) {
-				const activity = this.apRendererService.addContext(this.apRendererService.renderDelete(this.apRendererService.renderTombstone(`${this.config.url}/notes/${message.id}`), fromUser));
-				this.queueService.deliver(fromUser, activity, toUser.inbox);
+				//const activity = this.apRendererService.addContext(this.apRendererService.renderDelete(this.apRendererService.renderTombstone(`${this.config.url}/notes/${message.id}`), fromUser));
+				//this.queueService.deliver(fromUser, activity, toUser.inbox);
 			}
 		}/* else if (message.toRoomId) {
 			this.globalEventService.publishRoomChatStream(message.toRoomId, 'deleted', message.id);
diff --git a/packages/backend/src/server/api/endpoint-list.ts b/packages/backend/src/server/api/endpoint-list.ts
index 1428fca6cd..ba999e14fb 100644
--- a/packages/backend/src/server/api/endpoint-list.ts
+++ b/packages/backend/src/server/api/endpoint-list.ts
@@ -397,6 +397,7 @@ export * as 'users/search-by-username-and-host' from './endpoints/users/search-b
 export * as 'users/show' from './endpoints/users/show.js';
 export * as 'users/update-memo' from './endpoints/users/update-memo.js';
 export * as 'chat/messages/create' from './endpoints/chat/messages/create.js';
+export * as 'chat/messages/delete' from './endpoints/chat/messages/delete.js';
 export * as 'chat/messages/timeline' from './endpoints/chat/messages/timeline.js';
 export * as 'chat/history' from './endpoints/chat/history.js';
 export * as 'v2/admin/emoji/list' from './endpoints/v2/admin/emoji/list.js';
diff --git a/packages/backend/src/server/api/endpoints/chat/messages/delete.ts b/packages/backend/src/server/api/endpoints/chat/messages/delete.ts
new file mode 100644
index 0000000000..ff4f4bd43f
--- /dev/null
+++ b/packages/backend/src/server/api/endpoints/chat/messages/delete.ts
@@ -0,0 +1,54 @@
+/*
+ * SPDX-FileCopyrightText: syuilo and misskey-project
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+import { Inject, Injectable } from '@nestjs/common';
+import { Endpoint } from '@/server/api/endpoint-base.js';
+import { DI } from '@/di-symbols.js';
+import { GetterService } from '@/server/api/GetterService.js';
+import { ChatService } from '@/core/ChatService.js';
+import { ChatMessageEntityService } from '@/core/entities/ChatMessageEntityService.js';
+import { ApiError } from '@/server/api/error.js';
+
+export const meta = {
+	tags: ['chat'],
+
+	requireCredential: true,
+
+	kind: 'write:chat',
+
+	res: {
+	},
+
+	errors: {
+		noSuchMessage: {
+			message: 'No such message.',
+			code: 'NO_SUCH_MESSAGE',
+			id: '36b67f0e-66a6-414b-83df-992a55294f17',
+		},
+	},
+} as const;
+
+export const paramDef = {
+	type: 'object',
+	properties: {
+		messageId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['messageId'],
+} as const;
+
+@Injectable()
+export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-disable-line import/no-default-export
+	constructor(
+		private chatService: ChatService,
+	) {
+		super(meta, paramDef, async (ps, me) => {
+			const message = await this.chatService.findMyMessageById(me.id, ps.messageId);
+			if (message == null) {
+				throw new ApiError(meta.errors.noSuchMessage);
+			}
+			await this.chatService.deleteMessage(message);
+		});
+	}
+}
diff --git a/packages/frontend/src/pages/chat/room.message.vue b/packages/frontend/src/pages/chat/room.message.vue
index 3e60242be4..b2626b964d 100644
--- a/packages/frontend/src/pages/chat/room.message.vue
+++ b/packages/frontend/src/pages/chat/room.message.vue
@@ -26,15 +26,18 @@
 </template>
 
 <script lang="ts" setup>
-import { computed } from 'vue';
+import { computed, defineAsyncComponent } from 'vue';
 import * as mfm from 'mfm-js';
 import * as Misskey from 'misskey-js';
+import { url } from '@@/js/config.js';
+import type { MenuItem } from '@/types/menu.js';
 import { extractUrlFromMfm } from '@/utility/extract-url-from-mfm.js';
 import MkUrlPreview from '@/components/MkUrlPreview.vue';
 import { ensureSignin } from '@/i.js';
 import { misskeyApi } from '@/utility/misskey-api.js';
 import { i18n } from '@/i18n.js';
 import MkFukidashi from '@/components/MkFukidashi.vue';
+import * as os from '@/os.js';
 
 const $i = ensureSignin();
 
@@ -47,10 +50,36 @@ const props = defineProps<{
 const isMe = computed(() => props.message.fromUserId === $i.id);
 const urls = computed(() => props.message.text ? extractUrlFromMfm(mfm.parse(props.message.text)) : []);
 
-function del(): void {
-	misskeyApi('chat/messages/delete', {
-		messageId: props.message.id,
-	});
+function showMenu(ev: MouseEvent) {
+	const menu: MenuItem[] = [];
+	if (isMe.value) {
+		menu.push({
+			text: i18n.ts.delete,
+			icon: 'ti ti-trash',
+			danger: true,
+			action: () => {
+				misskeyApi('chat/messages/delete', {
+					messageId: props.message.id,
+				});
+			},
+		});
+	} else {
+		menu.push({
+			text: i18n.ts.reportAbuse,
+			icon: 'ti ti-exclamation-circle',
+			action: () => {
+				const localUrl = `${url}/chat/messages/${props.message.id}`;
+				const { dispose } = os.popup(defineAsyncComponent(() => import('@/components/MkAbuseReportWindow.vue')), {
+					user: props.user,
+					initialComment: `${localUrl}\n-----\n`,
+				}, {
+					closed: () => dispose(),
+				});
+			},
+		});
+	}
+
+	os.popupMenu(menu, ev.currentTarget ?? ev.target);
 }
 </script>
 
diff --git a/packages/misskey-js/etc/misskey-js.api.md b/packages/misskey-js/etc/misskey-js.api.md
index 754b238272..110525d3f7 100644
--- a/packages/misskey-js/etc/misskey-js.api.md
+++ b/packages/misskey-js/etc/misskey-js.api.md
@@ -965,6 +965,12 @@ type ChatMessagesCreateRequest = operations['chat___messages___create']['request
 // @public (undocumented)
 type ChatMessagesCreateResponse = operations['chat___messages___create']['responses']['200']['content']['application/json'];
 
+// @public (undocumented)
+type ChatMessagesDeleteRequest = operations['chat___messages___delete']['requestBody']['content']['application/json'];
+
+// @public (undocumented)
+type ChatMessagesDeleteResponse = operations['chat___messages___delete']['responses']['200']['content']['application/json'];
+
 // @public (undocumented)
 type ChatMessagesTimelineRequest = operations['chat___messages___timeline']['requestBody']['content']['application/json'];
 
@@ -1475,6 +1481,8 @@ declare namespace entities {
         ChatHistoryResponse,
         ChatMessagesCreateRequest,
         ChatMessagesCreateResponse,
+        ChatMessagesDeleteRequest,
+        ChatMessagesDeleteResponse,
         ChatMessagesTimelineRequest,
         ChatMessagesTimelineResponse,
         ClipsAddNoteRequest,
diff --git a/packages/misskey-js/src/autogen/apiClientJSDoc.ts b/packages/misskey-js/src/autogen/apiClientJSDoc.ts
index b3e330807f..8983f616e6 100644
--- a/packages/misskey-js/src/autogen/apiClientJSDoc.ts
+++ b/packages/misskey-js/src/autogen/apiClientJSDoc.ts
@@ -1556,6 +1556,17 @@ declare module '../api.js' {
       credential?: string | null,
     ): Promise<SwitchCaseResponseType<E, P>>;
 
+    /**
+     * No description provided.
+     * 
+     * **Credential required**: *Yes* / **Permission**: *write:chat*
+     */
+    request<E extends 'chat/messages/delete', P extends Endpoints[E]['req']>(
+      endpoint: E,
+      params: P,
+      credential?: string | null,
+    ): Promise<SwitchCaseResponseType<E, P>>;
+
     /**
      * No description provided.
      * 
diff --git a/packages/misskey-js/src/autogen/endpoint.ts b/packages/misskey-js/src/autogen/endpoint.ts
index 8514389bdd..61fd110bbf 100644
--- a/packages/misskey-js/src/autogen/endpoint.ts
+++ b/packages/misskey-js/src/autogen/endpoint.ts
@@ -211,6 +211,8 @@ import type {
 	ChatHistoryResponse,
 	ChatMessagesCreateRequest,
 	ChatMessagesCreateResponse,
+	ChatMessagesDeleteRequest,
+	ChatMessagesDeleteResponse,
 	ChatMessagesTimelineRequest,
 	ChatMessagesTimelineResponse,
 	ClipsAddNoteRequest,
@@ -734,6 +736,7 @@ export type Endpoints = {
 	'charts/users': { req: ChartsUsersRequest; res: ChartsUsersResponse };
 	'chat/history': { req: ChatHistoryRequest; res: ChatHistoryResponse };
 	'chat/messages/create': { req: ChatMessagesCreateRequest; res: ChatMessagesCreateResponse };
+	'chat/messages/delete': { req: ChatMessagesDeleteRequest; res: ChatMessagesDeleteResponse };
 	'chat/messages/timeline': { req: ChatMessagesTimelineRequest; res: ChatMessagesTimelineResponse };
 	'clips/add-note': { req: ClipsAddNoteRequest; res: EmptyResponse };
 	'clips/create': { req: ClipsCreateRequest; res: ClipsCreateResponse };
diff --git a/packages/misskey-js/src/autogen/entities.ts b/packages/misskey-js/src/autogen/entities.ts
index 9f38b0689b..4a05c4f1bb 100644
--- a/packages/misskey-js/src/autogen/entities.ts
+++ b/packages/misskey-js/src/autogen/entities.ts
@@ -214,6 +214,8 @@ export type ChatHistoryRequest = operations['chat___history']['requestBody']['co
 export type ChatHistoryResponse = operations['chat___history']['responses']['200']['content']['application/json'];
 export type ChatMessagesCreateRequest = operations['chat___messages___create']['requestBody']['content']['application/json'];
 export type ChatMessagesCreateResponse = operations['chat___messages___create']['responses']['200']['content']['application/json'];
+export type ChatMessagesDeleteRequest = operations['chat___messages___delete']['requestBody']['content']['application/json'];
+export type ChatMessagesDeleteResponse = operations['chat___messages___delete']['responses']['200']['content']['application/json'];
 export type ChatMessagesTimelineRequest = operations['chat___messages___timeline']['requestBody']['content']['application/json'];
 export type ChatMessagesTimelineResponse = operations['chat___messages___timeline']['responses']['200']['content']['application/json'];
 export type ClipsAddNoteRequest = operations['clips___add-note']['requestBody']['content']['application/json'];
diff --git a/packages/misskey-js/src/autogen/types.ts b/packages/misskey-js/src/autogen/types.ts
index 6e0346b935..baf6d69ba2 100644
--- a/packages/misskey-js/src/autogen/types.ts
+++ b/packages/misskey-js/src/autogen/types.ts
@@ -1376,6 +1376,15 @@ export type paths = {
      */
     post: operations['chat___messages___create'];
   };
+  '/chat/messages/delete': {
+    /**
+     * chat/messages/delete
+     * @description No description provided.
+     *
+     * **Credential required**: *Yes* / **Permission**: *write:chat*
+     */
+    post: operations['chat___messages___delete'];
+  };
   '/chat/messages/timeline': {
     /**
      * chat/messages/timeline
@@ -13844,6 +13853,60 @@ export type operations = {
       };
     };
   };
+  /**
+   * chat/messages/delete
+   * @description No description provided.
+   *
+   * **Credential required**: *Yes* / **Permission**: *write:chat*
+   */
+  chat___messages___delete: {
+    requestBody: {
+      content: {
+        'application/json': {
+          /** Format: misskey:id */
+          messageId: string;
+        };
+      };
+    };
+    responses: {
+      /** @description OK (with results) */
+      200: {
+        content: {
+          'application/json': unknown;
+        };
+      };
+      /** @description Client error */
+      400: {
+        content: {
+          'application/json': components['schemas']['Error'];
+        };
+      };
+      /** @description Authentication error */
+      401: {
+        content: {
+          'application/json': components['schemas']['Error'];
+        };
+      };
+      /** @description Forbidden error */
+      403: {
+        content: {
+          'application/json': components['schemas']['Error'];
+        };
+      };
+      /** @description I'm Ai */
+      418: {
+        content: {
+          'application/json': components['schemas']['Error'];
+        };
+      };
+      /** @description Internal server error */
+      500: {
+        content: {
+          'application/json': components['schemas']['Error'];
+        };
+      };
+    };
+  };
   /**
    * chat/messages/timeline
    * @description No description provided.