diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2156c8147416..e50dbfec9bd1 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -53,6 +53,7 @@
   4. フォローしていない非アクティブなユーザ
 - Fix: 一般ユーザーから見たユーザーのバッジの一覧に公開されていないものが含まれることがある問題を修正  
   (Cherry-picked from https://github.com/MisskeyIO/misskey/pull/652)
+- Fix: ユーザーのリアクション一覧でミュート/ブロックが機能していなかった問題を修正
 
 ### Misskey.js
 - Feat: `/drive/files/create` のリクエストに対応（`multipart/form-data`に対応）
diff --git a/packages/backend/src/misc/is-user-related.ts b/packages/backend/src/misc/is-user-related.ts
index 93c9b2b814bf..862d6e6a3839 100644
--- a/packages/backend/src/misc/is-user-related.ts
+++ b/packages/backend/src/misc/is-user-related.ts
@@ -4,6 +4,10 @@
  */
 
 export function isUserRelated(note: any, userIds: Set<string>, ignoreAuthor = false): boolean {
+	if (!note) {
+		return false;
+	}
+
 	if (userIds.has(note.userId) && !ignoreAuthor) {
 		return true;
 	}
diff --git a/packages/backend/src/server/api/endpoints/users/reactions.ts b/packages/backend/src/server/api/endpoints/users/reactions.ts
index aca883a052bb..7805ae328861 100644
--- a/packages/backend/src/server/api/endpoints/users/reactions.ts
+++ b/packages/backend/src/server/api/endpoints/users/reactions.ts
@@ -12,6 +12,7 @@ import { DI } from '@/di-symbols.js';
 import { CacheService } from '@/core/CacheService.js';
 import { UserEntityService } from '@/core/entities/UserEntityService.js';
 import { RoleService } from '@/core/RoleService.js';
+import { isUserRelated } from '@/misc/is-user-related.js';
 import { ApiError } from '../../error.js';
 
 export const meta = {
@@ -74,6 +75,7 @@ export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-
 		private roleService: RoleService,
 	) {
 		super(meta, paramDef, async (ps, me) => {
+			const userIdsWhoBlockingMe = me ? await this.cacheService.userBlockedCache.fetch(me.id) : new Set<string>();
 			const iAmModerator = me ? await this.roleService.isModerator(me) : false; // Moderators can see reactions of all users
 			if (!iAmModerator) {
 				const user = await this.cacheService.findUserById(ps.userId);
@@ -85,8 +87,15 @@ export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-
 				if ((me == null || me.id !== ps.userId) && !profile.publicReactions) {
 					throw new ApiError(meta.errors.reactionsNotPublic);
 				}
+
+				// early return if me is blocked by requesting user
+				if (userIdsWhoBlockingMe.has(ps.userId)) {
+					return [];
+				}
 			}
 
+			const userIdsWhoMeMuting = me ? await this.cacheService.userMutingsCache.fetch(me.id) : new Set<string>();
+
 			const query = this.queryService.makePaginationQuery(this.noteReactionsRepository.createQueryBuilder('reaction'),
 				ps.sinceId, ps.untilId, ps.sinceDate, ps.untilDate)
 				.andWhere('reaction.userId = :userId', { userId: ps.userId })
@@ -94,9 +103,15 @@ export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-
 
 			this.queryService.generateVisibilityQuery(query, me);
 
-			const reactions = await query
+			const reactions = (await query
 				.limit(ps.limit)
-				.getMany();
+				.getMany()).filter(reaction => {
+				if (reaction.note?.userId === ps.userId) return true; // we can see reactions to note of requesting user
+				if (me && isUserRelated(reaction.note, userIdsWhoBlockingMe)) return false;
+				if (me && isUserRelated(reaction.note, userIdsWhoMeMuting)) return false;
+
+				return true;
+			});
 
 			return await this.noteReactionEntityService.packMany(reactions, me, { withNote: true });
 		});