diff --git a/scripts/sync_version.py b/scripts/sync_version.py
index b128ede..c9c7056 100644
--- a/scripts/sync_version.py
+++ b/scripts/sync_version.py
@@ -91,6 +91,26 @@ def update_env_example(version: str) -> None:
             )
 
 
+def update_env_file(version: str) -> None:
+    """Update APP_VERSION in .env if it exists.
+
+    Args:
+        version: New version string to set
+    """
+    env_file = PROJECT_ROOT / ".env"
+    if env_file.exists():
+        content = env_file.read_text()
+        # Update if APP_VERSION is present
+        if 'APP_VERSION=' in content:
+            new_content = re.sub(
+                r'APP_VERSION=[^\n]+',
+                f'APP_VERSION={version}',
+                content,
+            )
+            env_file.write_text(new_content)
+            print(f"✓ Updated .env to {version}")
+
+
 def update_changelog(version: str) -> None:
     """Add version header to CHANGELOG.md if not present.
 
@@ -145,6 +165,7 @@ def main() -> int:
             print(f"📍 Current version from __init__.py: {version}")
 
         update_env_example(version)
+        update_env_file(version)
         update_changelog(version)
         print(f"\n✅ Version sync complete: {version}")
         return 0