diff --git a/locales/ja-JP.yml b/locales/ja-JP.yml
index f8ef41ea0..a5b1b3ed2 100644
--- a/locales/ja-JP.yml
+++ b/locales/ja-JP.yml
@@ -805,6 +805,7 @@ makeReactionsPublicDescription: "あなたがしたリアクション一覧を
 classic: "クラシック"
 muteThread: "スレッドをミュート"
 unmuteThread: "スレッドのミュートを解除"
+threadMuteNotificationsDesc: "このスレッドから表示する通知を選択します。グローバル通知設定も適用され、禁止が優先されます。"
 ffVisibility: "つながりの公開範囲"
 ffVisibilityDescription: "自分のフォロー/フォロワー情報の公開範囲を設定できます。"
 continueThread: "さらにスレッドを見る"
diff --git a/packages/backend/src/server/api/endpoints/notes/thread-muting/create.ts b/packages/backend/src/server/api/endpoints/notes/thread-muting/create.ts
index 3181041a8..f4bd4186d 100644
--- a/packages/backend/src/server/api/endpoints/notes/thread-muting/create.ts
+++ b/packages/backend/src/server/api/endpoints/notes/thread-muting/create.ts
@@ -1,5 +1,5 @@
 import { noteNotificationTypes } from 'foundkey-js';
-import { Notes, NoteThreadMutings } from '@/models/index.js';
+import { Notes, NoteThreadMutings, NoteWatchings } from '@/models/index.js';
 import { genId } from '@/misc/gen-id.js';
 import readNote from '@/services/note/read.js';
 import define from '../../../define.js';
@@ -62,4 +62,17 @@ export default define(meta, paramDef, async (ps, user) => {
 		userId: user.id,
 		mutingNotificationTypes: ps.mutingNotificationTypes,
 	});
+
+	// remove all note watchings in the muted thread
+	const notesThread = Notes.createQueryBuilder("notes")
+		.select("note.id")
+		.where({
+			threadId: note.threadId ?? note.id,
+		});
+
+	await NoteWatchings.createQueryBuilder()
+		.delete()
+		.where(`"note_watching"."noteId" IN (${ notesThread.getQuery() })`)
+		.setParameters(notesThread.getParameters())
+		.execute();
 });
diff --git a/packages/client/src/components/notification-setting-window.vue b/packages/client/src/components/notification-setting-window.vue
index 7bcf2768f..4edbda033 100644
--- a/packages/client/src/components/notification-setting-window.vue
+++ b/packages/client/src/components/notification-setting-window.vue
@@ -18,7 +18,7 @@
 			</MkSwitch>
 		</div>
 		<div v-if="!useGlobalSetting" class="_section">
-			<MkInfo>{{ i18n.ts.notificationSettingDesc }}</MkInfo>
+			<MkInfo>{{ message }}</MkInfo>
 			<MkButton inline @click="disableAll">{{ i18n.ts.disableAll }}</MkButton>
 			<MkButton inline @click="enableAll">{{ i18n.ts.enableAll }}</MkButton>
 			<MkSwitch v-for="ntype in notificationTypes" :key="ntype" v-model="typesMap[ntype]">{{ i18n.t(`_notification._types.${ntype}`) }}</MkSwitch>
@@ -44,10 +44,12 @@ const props = withDefaults(defineProps<{
 	includingTypes?: typeof foundkey.notificationTypes[number][] | null;
 	notificationTypes?: typeof foundkey.notificationTypes[number][] | null;
 	showGlobalToggle?: boolean;
+	message?: string,
 }>(), {
 	includingTypes: () => [],
 	notificationTypes: () => [],
 	showGlobalToggle: true,
+	message: i18n.ts.notificationSettingDesc,
 });
 
 let includingTypes = $computed(() => props.includingTypes || []);