diff --git a/ui/hud_overlay.py b/ui/hud_overlay.py
index 0e83010..bd373ec 100644
--- a/ui/hud_overlay.py
+++ b/ui/hud_overlay.py
@@ -14,6 +14,28 @@ from typing import Optional, Dict, Any
 if sys.platform == 'win32':
     import ctypes
     from ctypes import wintypes
+    
+    # Windows API constants for window detection
+    GW_OWNER = 4
+    
+    # GetForegroundWindow function
+    user32 = ctypes.windll.user32
+    GetForegroundWindow = user32.GetForegroundWindow
+    GetForegroundWindow.restype = wintypes.HWND
+    
+    # GetWindowText functions
+    GetWindowTextLengthW = user32.GetWindowTextLengthW
+    GetWindowTextLengthW.argtypes = [wintypes.HWND]
+    GetWindowTextLengthW.restype = ctypes.c_int
+    
+    GetWindowTextW = user32.GetWindowTextW
+    GetWindowTextW.argtypes = [wintypes.HWND, wintypes.LPWSTR, ctypes.c_int]
+    GetWindowTextW.restype = ctypes.c_int
+    
+    # FindWindow function
+    FindWindowW = user32.FindWindowW
+    FindWindowW.argtypes = [wintypes.LPCWSTR, wintypes.LPCWSTR]
+    FindWindowW.restype = wintypes.HWND
 
 from PyQt6.QtWidgets import (
     QApplication, QWidget, QVBoxLayout, QHBoxLayout,
@@ -124,10 +146,21 @@ class HUDOverlay(QWidget):
         self._drag_offset = QPoint()
         self._modifier_pressed = False
         
+        # Game window detection
+        self._auto_hide_with_game = True  # Auto-hide when game not focused
+        self._game_window_title = "Entropia Universe"  # Window title to track
+        self._was_visible_before_unfocus = False
+        
         # Timer for session time updates
         self._timer = QTimer(self)
         self._timer.timeout.connect(self._update_session_time)
         
+        # Timer for game window detection (Windows only)
+        self._window_check_timer = QTimer(self)
+        self._window_check_timer.timeout.connect(self._check_game_window)
+        if sys.platform == 'win32':
+            self._window_check_timer.start(500)  # Check every 500ms
+        
         self._setup_window()
         self._setup_ui()
         self._load_position()
@@ -609,6 +642,51 @@ class HUDOverlay(QWidget):
             self._stats.session_time = datetime.now() - self._session_start
             self._update_time_display()
     
+    def _check_game_window(self) -> None:
+        """
+        Check if Entropia Universe window is in foreground.
+        Auto-hide HUD when game is not focused (optional feature).
+        """
+        if not self._auto_hide_with_game or sys.platform != 'win32':
+            return
+        
+        try:
+            # Get foreground window title
+            hwnd = GetForegroundWindow()
+            if hwnd:
+                length = GetWindowTextLengthW(hwnd)
+                if length > 0:
+                    buffer = ctypes.create_unicode_buffer(length + 1)
+                    GetWindowTextW(hwnd, buffer, length + 1)
+                    title = buffer.value
+                    
+                    # Check if game is in foreground
+                    is_game_focused = self._game_window_title in title
+                    
+                    if is_game_focused:
+                        # Game is focused - show HUD if it was hidden
+                        if self._was_visible_before_unfocus and not self.isVisible():
+                            self.show()
+                    else:
+                        # Game not focused - hide HUD if visible
+                        if self.isVisible():
+                            self._was_visible_before_unfocus = True
+                            self.hide()
+                        else:
+                            self._was_visible_before_unfocus = False
+        except Exception:
+            # Silently ignore errors (e.g., Windows API issues)
+            pass
+    
+    def set_auto_hide_with_game(self, enabled: bool) -> None:
+        """
+        Enable/disable auto-hide when game not focused.
+        
+        Args:
+            enabled: True to auto-hide HUD when game loses focus
+        """
+        self._auto_hide_with_game = enabled
+    
     def _update_time_display(self) -> None:
         """Update the time label."""
         total_seconds = int(self._stats.session_time.total_seconds())