diff --git a/server/config.py b/server/config.py
index 9b02125..4e9ff71 100644
--- a/server/config.py
+++ b/server/config.py
@@ -142,6 +142,7 @@ class ServerConfig:
     MAX_PLAYERS_PER_ROOM: int = 6
     ROOM_TIMEOUT_MINUTES: int = 60
     ROOM_CODE_LENGTH: int = 4
+    ROOM_IDLE_TIMEOUT_SECONDS: int = 300  # 5 minutes of inactivity
 
     # Security (for future auth system)
     SECRET_KEY: str = ""
@@ -198,6 +199,7 @@ class ServerConfig:
             MAX_PLAYERS_PER_ROOM=get_env_int("MAX_PLAYERS_PER_ROOM", 6),
             ROOM_TIMEOUT_MINUTES=get_env_int("ROOM_TIMEOUT_MINUTES", 60),
             ROOM_CODE_LENGTH=get_env_int("ROOM_CODE_LENGTH", 4),
+            ROOM_IDLE_TIMEOUT_SECONDS=get_env_int("ROOM_IDLE_TIMEOUT_SECONDS", 300),
             SECRET_KEY=get_env("SECRET_KEY", ""),
             INVITE_ONLY=get_env_bool("INVITE_ONLY", True),
             DAILY_OPEN_SIGNUPS=get_env_int("DAILY_OPEN_SIGNUPS", 0),
diff --git a/server/handlers.py b/server/handlers.py
index 3c9c76f..2bcaab4 100644
--- a/server/handlers.py
+++ b/server/handlers.py
@@ -69,6 +69,7 @@ async def handle_create_room(data: dict, ctx: ConnectionContext, *, room_manager
     player_name = ctx.authenticated_user.username if ctx.authenticated_user else data.get("player_name", "Player")
     room = room_manager.create_room()
     room.add_player(ctx.player_id, player_name, ctx.websocket, ctx.auth_user_id)
+    room.touch()
     ctx.current_room = room
 
     await ctx.websocket.send_json({
@@ -114,6 +115,7 @@ async def handle_join_room(data: dict, ctx: ConnectionContext, *, room_manager,
         return
 
     room.add_player(ctx.player_id, player_name, ctx.websocket, ctx.auth_user_id)
+    room.touch()
     ctx.current_room = room
 
     await ctx.websocket.send_json({
@@ -189,6 +191,7 @@ async def handle_remove_cpu(data: dict, ctx: ConnectionContext, **kw) -> None:
 async def handle_start_game(data: dict, ctx: ConnectionContext, *, broadcast_game_state, check_and_run_cpu_turn, **kw) -> None:
     if not ctx.current_room:
         return
+    ctx.current_room.touch()
 
     room_player = ctx.current_room.get_player(ctx.player_id)
     if not room_player or not room_player.is_host:
@@ -235,6 +238,7 @@ async def handle_start_game(data: dict, ctx: ConnectionContext, *, broadcast_gam
 async def handle_flip_initial(data: dict, ctx: ConnectionContext, *, broadcast_game_state, check_and_run_cpu_turn, **kw) -> None:
     if not ctx.current_room:
         return
+    ctx.current_room.touch()
 
     positions = data.get("positions", [])
     async with ctx.current_room.game_lock:
@@ -250,6 +254,7 @@ async def handle_flip_initial(data: dict, ctx: ConnectionContext, *, broadcast_g
 async def handle_draw(data: dict, ctx: ConnectionContext, *, broadcast_game_state, **kw) -> None:
     if not ctx.current_room:
         return
+    ctx.current_room.touch()
 
     source = data.get("source", "deck")
     async with ctx.current_room.game_lock:
@@ -277,6 +282,7 @@ async def handle_draw(data: dict, ctx: ConnectionContext, *, broadcast_game_stat
 async def handle_swap(data: dict, ctx: ConnectionContext, *, broadcast_game_state, check_and_run_cpu_turn, **kw) -> None:
     if not ctx.current_room:
         return
+    ctx.current_room.touch()
 
     position = data.get("position", 0)
     async with ctx.current_room.game_lock:
@@ -303,6 +309,7 @@ async def handle_swap(data: dict, ctx: ConnectionContext, *, broadcast_game_stat
 async def handle_discard(data: dict, ctx: ConnectionContext, *, broadcast_game_state, check_and_run_cpu_turn, **kw) -> None:
     if not ctx.current_room:
         return
+    ctx.current_room.touch()
 
     async with ctx.current_room.game_lock:
         drawn_card = ctx.current_room.game.drawn_card
@@ -349,6 +356,7 @@ async def handle_cancel_draw(data: dict, ctx: ConnectionContext, *, broadcast_ga
 async def handle_flip_card(data: dict, ctx: ConnectionContext, *, broadcast_game_state, check_and_run_cpu_turn, **kw) -> None:
     if not ctx.current_room:
         return
+    ctx.current_room.touch()
 
     position = data.get("position", 0)
     async with ctx.current_room.game_lock:
@@ -370,6 +378,7 @@ async def handle_flip_card(data: dict, ctx: ConnectionContext, *, broadcast_game
 async def handle_skip_flip(data: dict, ctx: ConnectionContext, *, broadcast_game_state, check_and_run_cpu_turn, **kw) -> None:
     if not ctx.current_room:
         return
+    ctx.current_room.touch()
 
     async with ctx.current_room.game_lock:
         player = ctx.current_room.game.get_player(ctx.player_id)
@@ -386,6 +395,7 @@ async def handle_skip_flip(data: dict, ctx: ConnectionContext, *, broadcast_game
 async def handle_flip_as_action(data: dict, ctx: ConnectionContext, *, broadcast_game_state, check_and_run_cpu_turn, **kw) -> None:
     if not ctx.current_room:
         return
+    ctx.current_room.touch()
 
     position = data.get("position", 0)
     async with ctx.current_room.game_lock:
@@ -406,6 +416,7 @@ async def handle_flip_as_action(data: dict, ctx: ConnectionContext, *, broadcast
 async def handle_knock_early(data: dict, ctx: ConnectionContext, *, broadcast_game_state, check_and_run_cpu_turn, **kw) -> None:
     if not ctx.current_room:
         return
+    ctx.current_room.touch()
 
     async with ctx.current_room.game_lock:
         player = ctx.current_room.game.get_player(ctx.player_id)
@@ -424,6 +435,7 @@ async def handle_knock_early(data: dict, ctx: ConnectionContext, *, broadcast_ga
 async def handle_next_round(data: dict, ctx: ConnectionContext, *, broadcast_game_state, check_and_run_cpu_turn, **kw) -> None:
     if not ctx.current_room:
         return
+    ctx.current_room.touch()
 
     room_player = ctx.current_room.get_player(ctx.player_id)
     if not room_player or not room_player.is_host:
@@ -467,6 +479,7 @@ async def handle_leave_game(data: dict, ctx: ConnectionContext, *, handle_player
 async def handle_end_game(data: dict, ctx: ConnectionContext, *, room_manager, cleanup_room_profiles, **kw) -> None:
     if not ctx.current_room:
         return
+    ctx.current_room.touch()
 
     room_player = ctx.current_room.get_player(ctx.player_id)
     if not room_player or not room_player.is_host:
diff --git a/server/main.py b/server/main.py
index 0a7bb0f..b6369be 100644
--- a/server/main.py
+++ b/server/main.py
@@ -64,6 +64,7 @@ _matchmaking_service = None
 _replay_service = None
 _spectator_manager = None
 _leaderboard_refresh_task = None
+_room_cleanup_task = None
 _redis_client = None
 _rate_limiter = None
 _shutdown_event = asyncio.Event()
@@ -83,6 +84,60 @@ async def _periodic_leaderboard_refresh():
             logger.error(f"Leaderboard refresh failed: {e}")
 
 
+async def _periodic_room_cleanup():
+    """Periodic task to clean up rooms idle for longer than ROOM_IDLE_TIMEOUT_SECONDS."""
+    import time
+    while True:
+        try:
+            await asyncio.sleep(60)
+            now = time.time()
+            timeout = config.ROOM_IDLE_TIMEOUT_SECONDS
+            stale_rooms = [
+                room for room in room_manager.rooms.values()
+                if now - room.last_activity > timeout
+            ]
+            for room in stale_rooms:
+                logger.info(
+                    f"Cleaning up stale room {room.code} "
+                    f"(idle {int(now - room.last_activity)}s, "
+                    f"{len(room.players)} players)"
+                )
+                # Cancel CPU turn task
+                if room.cpu_turn_task:
+                    room.cpu_turn_task.cancel()
+                    try:
+                        await room.cpu_turn_task
+                    except (asyncio.CancelledError, Exception):
+                        pass
+                    room.cpu_turn_task = None
+
+                # Notify and close human WebSocket connections
+                for player in list(room.players.values()):
+                    if player.websocket and not player.is_cpu:
+                        try:
+                            await player.websocket.send_json({
+                                "type": "room_expired",
+                                "message": "Room closed due to inactivity",
+                            })
+                            await player.websocket.close(code=4002, reason="Room expired")
+                        except Exception:
+                            pass
+
+                # Clean up players and profiles
+                room_code = room.code
+                for cpu in list(room.get_cpu_players()):
+                    room.remove_player(cpu.id)
+                cleanup_room_profiles(room_code)
+                room_manager.remove_room(room_code)
+
+            if stale_rooms:
+                logger.info(f"Cleaned up {len(stale_rooms)} stale room(s)")
+        except asyncio.CancelledError:
+            break
+        except Exception as e:
+            logger.error(f"Room cleanup failed: {e}")
+
+
 async def _init_redis():
     """Initialize Redis client, rate limiter, and signup limiter."""
     global _redis_client, _rate_limiter
@@ -254,6 +309,14 @@ async def _shutdown_services():
     reset_all_profiles()
     logger.info("All rooms and CPU profiles cleaned up")
 
+    if _room_cleanup_task:
+        _room_cleanup_task.cancel()
+        try:
+            await _room_cleanup_task
+        except asyncio.CancelledError:
+            pass
+        logger.info("Room cleanup task stopped")
+
     if _leaderboard_refresh_task:
         _leaderboard_refresh_task.cancel()
         try:
@@ -312,6 +375,11 @@ async def lifespan(app: FastAPI):
         room_manager=room_manager,
     )
 
+    # Start periodic room cleanup
+    global _room_cleanup_task
+    _room_cleanup_task = asyncio.create_task(_periodic_room_cleanup())
+    logger.info(f"Room cleanup task started (timeout={config.ROOM_IDLE_TIMEOUT_SECONDS}s)")
+
     logger.info(f"Golf server started (environment={config.ENVIRONMENT})")
 
     yield
@@ -761,6 +829,8 @@ async def _run_cpu_chain(room: Room):
         if not room_player or not room_player.is_cpu:
             return
 
+        room.touch()
+
         # Brief pause before CPU starts - animations are faster now
         await asyncio.sleep(0.25)
 
diff --git a/server/room.py b/server/room.py
index 57076cb..ebf97f7 100644
--- a/server/room.py
+++ b/server/room.py
@@ -14,6 +14,7 @@ A Room contains:
 import asyncio
 import random
 import string
+import time
 from dataclasses import dataclass, field
 from typing import Optional
 
@@ -70,6 +71,11 @@ class Room:
     game_log_id: Optional[str] = None
     game_lock: asyncio.Lock = field(default_factory=asyncio.Lock)
     cpu_turn_task: Optional[asyncio.Task] = None
+    last_activity: float = field(default_factory=time.time)
+
+    def touch(self) -> None:
+        """Update last_activity timestamp to mark room as active."""
+        self.last_activity = time.time()
 
     def add_player(
         self,