diff --git a/app/repository/chat_tab_repository.py b/app/repository/chat_tab_repository.py
index 472056f..0f40f3a 100644
--- a/app/repository/chat_tab_repository.py
+++ b/app/repository/chat_tab_repository.py
@@ -56,7 +56,7 @@ def updated_chat_tab(self, id: str, new_name: str | None) -> ChatTabInDB | None:
 
             # 데이터 업데이트
             cursor.execute(
-                "UPDATE chat_tab SET name = ?, updated_at = datetime('now', 'localtime') WHERE id = ?",
+                "UPDATE chat_tab SET name = ?, updated_at = datetime('now') WHERE id = ?",
                 (new_name, id),
             )
             conn.commit()
@@ -73,6 +73,20 @@ def updated_chat_tab(self, id: str, new_name: str | None) -> ChatTabInDB | None:
             if conn:
                 conn.close()
 
+    def update_tab_timestamp(self, id: str) -> bool:
+        """지정된 ID의 채팅 탭의 updated_at 타임스탬프를 현재 시간으로 업데이트합니다."""
+        db_path = get_db_path()
+        conn = None
+        try:
+            conn = sqlite3.connect(str(db_path), timeout=10)
+            cursor = conn.cursor()
+            cursor.execute("UPDATE chat_tab SET updated_at = datetime('now') WHERE id = ?", (id,))
+            conn.commit()
+            return cursor.rowcount > 0
+        finally:
+            if conn:
+                conn.close()
+
     def delete_chat_tab(self, id: str) -> bool:
         """채팅 탭ID에 해당하는 ChatTab을 삭제하고, 성공 여부를 반환합니다."""
         db_path = get_db_path()
diff --git a/app/services/chat_message_service.py b/app/services/chat_message_service.py
index 6df4db8..9f2015d 100644
--- a/app/services/chat_message_service.py
+++ b/app/services/chat_message_service.py
@@ -10,24 +10,24 @@
 from app.core.status import CommonCode
 from app.core.utils import generate_prefixed_uuid
 from app.repository.chat_message_repository import ChatMessageRepository, chat_message_repository
+from app.repository.chat_tab_repository import ChatTabRepository, chat_tab_repository
 from app.schemas.chat_message.base_model import validate_chat_tab_id_format
 from app.schemas.chat_message.db_model import ChatMessageInDB
 from app.schemas.chat_message.request_model import ChatMessagesReqeust
 from app.schemas.chat_message.response_model import ALLChatMessagesResponseByTab, ChatMessagesResponse
 
 chat_message_repository_dependency = Depends(lambda: chat_message_repository)
-
-# AI_SERVER_URL = os.getenv("ENV_AI_SERVER_URL")
-
-# if not AI_SERVER_URL:
-#     raise APIException(CommonCode.FAIL_AI_SERVER_CONNECTION)
-#
-# url: str = AI_SERVER_URL
+chat_tab_repository_dependency = Depends(lambda: chat_tab_repository)
 
 
 class ChatMessageService:
-    def __init__(self, repository: ChatMessageRepository = chat_message_repository):
+    def __init__(
+        self,
+        repository: ChatMessageRepository = chat_message_repository,
+        chat_tab_repo: ChatTabRepository = chat_tab_repository,
+    ):
         self.repository = repository
+        self.chat_tab_repository = chat_tab_repo
         self._ai_server_url = None
 
     def _get_ai_server_url(self) -> str:
@@ -71,6 +71,9 @@ async def create_chat_message(self, request: ChatMessagesReqeust) -> ChatMessage
         # 4. AI 서버 응답 저장
         response = self._transform_ai_response_to_db_models(request, ai_response)
 
+        # 5. 채팅 탭의 updated_at 갱신
+        self.chat_tab_repository.update_tab_timestamp(request.chat_tab_id)
+
         # DB 모델을 API 응답 모델로 변환
         response_data = ChatMessagesResponse.model_validate(response)