diff --git a/packages/backend/src/core/CacheService.ts b/packages/backend/src/core/CacheService.ts
index ef3abec1911e..41ecc369cfaa 100644
--- a/packages/backend/src/core/CacheService.ts
+++ b/packages/backend/src/core/CacheService.ts
@@ -85,6 +85,7 @@ export class CacheService implements OnApplicationShutdown {
 		this.uriPersonCache = new MemoryKVCache<MiUser | null, string | null>(Infinity, {
 			toMapConverter: user => {
 				if (user === null) return null;
+				if (user.isDeleted) return null;
 
 				userByIdCache.set(user.id, user);
 				return user.id;
diff --git a/packages/backend/src/core/activitypub/ApDbResolverService.ts b/packages/backend/src/core/activitypub/ApDbResolverService.ts
index 143f89c3687d..f6b70ead4455 100644
--- a/packages/backend/src/core/activitypub/ApDbResolverService.ts
+++ b/packages/backend/src/core/activitypub/ApDbResolverService.ts
@@ -106,12 +106,12 @@ export class ApDbResolverService implements OnApplicationShutdown {
 
 			return await this.cacheService.userByIdCache.fetchMaybe(
 				parsed.id,
-				() => this.usersRepository.findOneBy({ id: parsed.id }).then(x => x ?? undefined),
+				() => this.usersRepository.findOneBy({ id: parsed.id, isDeleted: false }).then(x => x ?? undefined),
 			) as MiLocalUser | undefined ?? null;
 		} else {
 			return await this.cacheService.uriPersonCache.fetch(
 				parsed.uri,
-				() => this.usersRepository.findOneBy({ uri: parsed.uri }),
+				() => this.usersRepository.findOneBy({ uri: parsed.uri, isDeleted: false }),
 			) as MiRemoteUser | null;
 		}
 	}
@@ -136,8 +136,12 @@ export class ApDbResolverService implements OnApplicationShutdown {
 
 		if (key == null) return null;
 
+		const user = await this.cacheService.findUserById(key.userId).catch(() => null) as MiRemoteUser | null;
+		if (user == null) return null;
+		if (user.isDeleted) return null;
+
 		return {
-			user: await this.cacheService.findUserById(key.userId) as MiRemoteUser,
+			user,
 			key,
 		};
 	}
@@ -151,6 +155,7 @@ export class ApDbResolverService implements OnApplicationShutdown {
 		key: MiUserPublickey | null;
 	} | null> {
 		const user = await this.apPersonService.resolvePerson(uri) as MiRemoteUser;
+		if (user.isDeleted) return null;
 
 		const key = await this.publicKeyByUserIdCache.fetch(
 			user.id,
diff --git a/packages/backend/src/core/activitypub/ApInboxService.ts b/packages/backend/src/core/activitypub/ApInboxService.ts
index 526b04b292be..6803def063be 100644
--- a/packages/backend/src/core/activitypub/ApInboxService.ts
+++ b/packages/backend/src/core/activitypub/ApInboxService.ts
@@ -35,6 +35,7 @@ import { ApResolverService } from './ApResolverService.js';
 import { ApAudienceService } from './ApAudienceService.js';
 import { ApPersonService } from './models/ApPersonService.js';
 import { ApQuestionService } from './models/ApQuestionService.js';
+import { CacheService } from '@/core/CacheService.js';
 import type { Resolver } from './ApResolverService.js';
 import type { IAccept, IAdd, IAnnounce, IBlock, ICreate, IDelete, IFlag, IFollow, ILike, IObject, IReject, IRemove, IUndo, IUpdate, IMove } from './type.js';
 
@@ -82,6 +83,7 @@ export class ApInboxService {
 		private apPersonService: ApPersonService,
 		private apQuestionService: ApQuestionService,
 		private queueService: QueueService,
+		private cacheService: CacheService,
 	) {
 		this.logger = this.apLoggerService.logger;
 	}
@@ -479,6 +481,9 @@ export class ApInboxService {
 			isDeleted: true,
 		});
 
+		this.cacheService.uriPersonCache.delete(actor.uri);
+		this.cacheService.userByIdCache.delete(actor.id);
+
 		return `ok: queued ${job.name} ${job.id}`;
 	}