diff --git a/README.md b/README.md
index 506441d..8b09924 100644
--- a/README.md
+++ b/README.md
@@ -27,11 +27,16 @@ This project uses Python 3 and `uv` for dependency management. To set up the env
 Please refer to the [arcade-button-wiring.md](arcade-button-wiring.md) file for detailed instructions on how to connect the arcade button and its LED to the Raspberry Pi's GPIO pins.
 
 ## Usage
-1. Make sure your audio file (`Laid Back - Sunshine Reggae.mp3` or any other MP3 you prefer) is in the project directory.
+1. Make sure your audio file (`Laid Back - Sunshine Reggae.mp3` or any other MP3 you prefer) is in the project directory, or set a custom path.
 2. Run the alarm clock script manually:
    ```bash
+   # Use the default music file or the MUSIC_FILE environment variable
    python3 wecker.py
+
+   # Or pass a custom music file directly
+   python3 wecker.py --music-file /path/to/your/alarm.mp3
    ```
+   The music file is resolved in this order: `--music-file` argument, `MUSIC_FILE` environment variable, default `Laid Back - Sunshine Reggae.mp3`.
 
 ## Automating and Managing Alarms (GraphQL API)
 
diff --git a/tests/test_wecker.py b/tests/test_wecker.py
index 1c80612..e6588b1 100644
--- a/tests/test_wecker.py
+++ b/tests/test_wecker.py
@@ -124,3 +124,15 @@ def test_blinking_updates_time_correctly(mock_time, mock_gpio, mock_pygame):
 
     assert clock.state == wecker.STATE_WAIT_FOR_INPUT
     assert clock.last_interaction_time == 200.0
+
+
+def test_setup_uses_env_music_file(mock_gpio, mock_pygame, monkeypatch):
+    monkeypatch.setenv("MUSIC_FILE", "/custom/track.mp3")
+    wecker.setup()
+    mock_pygame.mixer.music.load.assert_called_with("/custom/track.mp3")
+
+
+def test_setup_music_file_argument_overrides_env(mock_gpio, mock_pygame, monkeypatch):
+    monkeypatch.setenv("MUSIC_FILE", "/env/track.mp3")
+    wecker.setup(music_file="/arg/track.mp3")
+    mock_pygame.mixer.music.load.assert_called_with("/arg/track.mp3")
diff --git a/wecker.py b/wecker.py
index 6534c94..cb5ddeb 100644
--- a/wecker.py
+++ b/wecker.py
@@ -63,8 +63,14 @@ BUTTON_PIN = 17
 LED_PIN = 27
 
 
-def setup():
+DEFAULT_MUSIC_FILE = "Laid Back - Sunshine Reggae.mp3"
+
+
+def setup(music_file: str | None = None):
     """Initialize GPIO and audio hardware. Call once before running."""
+    if music_file is None:
+        music_file = os.environ.get("MUSIC_FILE", DEFAULT_MUSIC_FILE)
+
     GPIO.setmode(GPIO.BCM)
     GPIO.setup(LED_PIN, GPIO.OUT)
     GPIO.setup(BUTTON_PIN, GPIO.IN, pull_up_down=GPIO.PUD_UP)
@@ -74,7 +80,7 @@ def setup():
     pygame.mixer.init()
 
     try:
-        pygame.mixer.music.load("Laid Back - Sunshine Reggae.mp3")
+        pygame.mixer.music.load(music_file)
         pygame.mixer.music.set_volume(1.0)
     except Exception as e:
         logging.error(f"Error loading audio file: {e}")
@@ -200,8 +206,8 @@ class AlarmClock:
         return True  # Keep running
 
 
-def run_alarm(test_mode=False):
-    setup()
+def run_alarm(test_mode=False, music_file: str | None = None):
+    setup(music_file=music_file)
     logging.info("Alarm clock started. Music is playing in an endless loop.")
     if "pygame" in globals() and hasattr(pygame, "mixer") and pygame.mixer.get_init():
         pygame.mixer.music.play(-1)
@@ -231,9 +237,19 @@ def run_alarm(test_mode=False):
 
 
 if __name__ == "__main__":
+    import argparse
+
+    parser = argparse.ArgumentParser(description="Raspberry Pi alarm clock.")
+    parser.add_argument(
+        "--music-file",
+        default=os.environ.get("MUSIC_FILE", DEFAULT_MUSIC_FILE),
+        help="Path to the MP3 file to play (default: $MUSIC_FILE or default track).",
+    )
+    args = parser.parse_args()
+
     ensure_single_instance()
     try:
-        run_alarm()
+        run_alarm(music_file=args.music_file)
     finally:
         pygame.mixer.quit()
         GPIO.cleanup()