diff --git a/CHANGELOG.md b/CHANGELOG.md
index a31be063f0..04acc11ac3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -21,7 +21,7 @@
 ### Server
 - Enhance: セキュリティ向上のため、ログイン時にメール通知を行うように
 - Enhance: 自分とモデレーター以外のユーザーから二要素認証関連のデータが取得できないように
-
+- Enhance: 通報および通報解決時に送出されるSystemWebhookにユーザ情報を含めるように ( #14697 )
 
 ## 2024.9.0
 
diff --git a/packages/backend/src/core/AbuseReportNotificationService.ts b/packages/backend/src/core/AbuseReportNotificationService.ts
index fe2c63e7d6..fb7c7bd2c3 100644
--- a/packages/backend/src/core/AbuseReportNotificationService.ts
+++ b/packages/backend/src/core/AbuseReportNotificationService.ts
@@ -22,6 +22,7 @@ import { RoleService } from '@/core/RoleService.js';
 import { RecipientMethod } from '@/models/AbuseReportNotificationRecipient.js';
 import { ModerationLogService } from '@/core/ModerationLogService.js';
 import { SystemWebhookService } from '@/core/SystemWebhookService.js';
+import { UserEntityService } from '@/core/entities/UserEntityService.js';
 import { IdService } from './IdService.js';
 
 @Injectable()
@@ -42,6 +43,7 @@ export class AbuseReportNotificationService implements OnApplicationShutdown {
 		private emailService: EmailService,
 		private moderationLogService: ModerationLogService,
 		private globalEventService: GlobalEventService,
+		private userEntityService: UserEntityService,
 	) {
 		this.redisForSub.on('message', this.onMessage);
 	}
@@ -135,6 +137,26 @@ export class AbuseReportNotificationService implements OnApplicationShutdown {
 			return;
 		}
 
+		const usersMap = await this.userEntityService.packMany(
+			[
+				...new Set([
+					...abuseReports.map(it => it.reporter ?? it.reporterId),
+					...abuseReports.map(it => it.targetUser ?? it.targetUserId),
+					...abuseReports.map(it => it.assignee ?? it.assigneeId),
+				].filter(x => x != null)),
+			],
+			null,
+			{ schema: 'UserLite' },
+		).then(it => new Map(it.map(it => [it.id, it])));
+		const convertedReports = abuseReports.map(it => {
+			return {
+				...it,
+				reporter: usersMap.get(it.reporterId),
+				targetUser: usersMap.get(it.targetUserId),
+				assignee: it.assigneeId ? usersMap.get(it.assigneeId) : null,
+			};
+		});
+
 		const recipientWebhookIds = await this.fetchWebhookRecipients()
 			.then(it => it
 				.filter(it => it.isActive && it.systemWebhookId && it.method === 'webhook')
@@ -142,7 +164,7 @@ export class AbuseReportNotificationService implements OnApplicationShutdown {
 				.filter(x => x != null));
 		for (const webhookId of recipientWebhookIds) {
 			await Promise.all(
-				abuseReports.map(it => {
+				convertedReports.map(it => {
 					return this.systemWebhookService.enqueueSystemWebhook(
 						webhookId,
 						type,
diff --git a/packages/backend/src/core/WebhookTestService.ts b/packages/backend/src/core/WebhookTestService.ts
index c2764f30e8..149c753d4c 100644
--- a/packages/backend/src/core/WebhookTestService.ts
+++ b/packages/backend/src/core/WebhookTestService.ts
@@ -15,8 +15,14 @@ import { QueueService } from '@/core/QueueService.js';
 
 const oneDayMillis = 24 * 60 * 60 * 1000;
 
-function generateAbuseReport(override?: Partial<MiAbuseUserReport>): MiAbuseUserReport {
-	return {
+type AbuseUserReportDto = Omit<MiAbuseUserReport, 'targetUser' | 'reporter' | 'assignee'> & {
+	targetUser: Packed<'UserLite'> | null,
+	reporter: Packed<'UserLite'> | null,
+	assignee: Packed<'UserLite'> | null,
+};
+
+function generateAbuseReport(override?: Partial<MiAbuseUserReport>): AbuseUserReportDto {
+	const result: MiAbuseUserReport = {
 		id: 'dummy-abuse-report1',
 		targetUserId: 'dummy-target-user',
 		targetUser: null,
@@ -31,6 +37,13 @@ function generateAbuseReport(override?: Partial<MiAbuseUserReport>): MiAbuseUser
 		reporterHost: null,
 		...override,
 	};
+
+	return {
+		...result,
+		targetUser: result.targetUser ? toPackedUserLite(result.targetUser) : null,
+		reporter: result.reporter ? toPackedUserLite(result.reporter) : null,
+		assignee: result.assignee ? toPackedUserLite(result.assignee) : null,
+	};
 }
 
 function generateDummyUser(override?: Partial<MiUser>): MiUser {
@@ -268,7 +281,8 @@ const dummyUser3 = generateDummyUser({
 
 @Injectable()
 export class WebhookTestService {
-	public static NoSuchWebhookError = class extends Error {};
+	public static NoSuchWebhookError = class extends Error {
+	};
 
 	constructor(
 		private userWebhookService: UserWebhookService,
diff --git a/packages/backend/test/unit/AbuseReportNotificationService.ts b/packages/backend/test/unit/AbuseReportNotificationService.ts
index e971659070..235af29f0d 100644
--- a/packages/backend/test/unit/AbuseReportNotificationService.ts
+++ b/packages/backend/test/unit/AbuseReportNotificationService.ts
@@ -5,6 +5,7 @@
 
 import { jest } from '@jest/globals';
 import { Test, TestingModule } from '@nestjs/testing';
+import { randomString } from '../utils.js';
 import { AbuseReportNotificationService } from '@/core/AbuseReportNotificationService.js';
 import {
 	AbuseReportNotificationRecipientRepository,
@@ -25,7 +26,7 @@ import { ModerationLogService } from '@/core/ModerationLogService.js';
 import { GlobalEventService } from '@/core/GlobalEventService.js';
 import { RecipientMethod } from '@/models/AbuseReportNotificationRecipient.js';
 import { SystemWebhookService } from '@/core/SystemWebhookService.js';
-import { randomString } from '../utils.js';
+import { UserEntityService } from '@/core/entities/UserEntityService.js';
 
 process.env.NODE_ENV = 'test';
 
@@ -110,6 +111,9 @@ describe('AbuseReportNotificationService', () => {
 					{
 						provide: SystemWebhookService, useFactory: () => ({ enqueueSystemWebhook: jest.fn() }),
 					},
+					{
+						provide: UserEntityService, useFactory: () => ({ pack: (v: any) => v }),
+					},
 					{
 						provide: EmailService, useFactory: () => ({ sendEmail: jest.fn() }),
 					},