diff --git a/packages/backend/src/server/oauth/OAuth2ProviderService.ts b/packages/backend/src/server/oauth/OAuth2ProviderService.ts
index 93cbaa403..61c89a425 100644
--- a/packages/backend/src/server/oauth/OAuth2ProviderService.ts
+++ b/packages/backend/src/server/oauth/OAuth2ProviderService.ts
@@ -1,3 +1,8 @@
+/*
+ * SPDX-FileCopyrightText: syuilo and other misskey contributors
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
 import dns from 'node:dns/promises';
 import { fileURLToPath } from 'node:url';
 import { Inject, Injectable } from '@nestjs/common';
diff --git a/packages/backend/test/e2e/oauth.ts b/packages/backend/test/e2e/oauth.ts
index 9048c2f7e..a029a0d4b 100644
--- a/packages/backend/test/e2e/oauth.ts
+++ b/packages/backend/test/e2e/oauth.ts
@@ -1,3 +1,8 @@
+/*
+ * SPDX-FileCopyrightText: syuilo and other misskey contributors
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
 /**
  * Basic OAuth tests to make sure the library is correctly integrated to Misskey
  * and not regressed by version updates or potential migration to another library.
diff --git a/packages/frontend/src/pages/oauth.vue b/packages/frontend/src/pages/oauth.vue
index 6a72057f4..0dbaed108 100644
--- a/packages/frontend/src/pages/oauth.vue
+++ b/packages/frontend/src/pages/oauth.vue
@@ -1,3 +1,8 @@
+<!--
+SPDX-FileCopyrightText: syuilo and other misskey contributors
+SPDX-License-Identifier: AGPL-3.0-only
+-->
+
 <template>
 <MkStickyContainer>
 	<template #header><MkPageHeader/></template>