diff --git a/download.py b/download.py
index 591bd7e..8932344 100644
--- a/download.py
+++ b/download.py
@@ -49,6 +49,19 @@ def login(session: requests.Session, email: str, password: str) -> bool:
     return True
 
 
+def parse_module_filter(arg: str) -> set[int]:
+    """Parse module filter like '1-3' or '4,5' or '1-3,5' into a set of 1-based indices."""
+    result = set()
+    for part in arg.split(","):
+        part = part.strip()
+        if "-" in part:
+            a, b = part.split("-", 1)
+            result.update(range(int(a), int(b) + 1))
+        else:
+            result.add(int(part))
+    return result
+
+
 def discover_modules(session: requests.Session) -> list[dict]:
     """Fetch course page and return list of {name, url, module_id}."""
     resp = session.get(COURSE_URL)
@@ -157,6 +170,14 @@ def main():
         log.error("Set COURSE_USERNAME and COURSE_PASSWORD in .env")
         sys.exit(1)
 
+    # Parse --modules filter (e.g. "4-5" or "1,3,5")
+    module_filter = None
+    if "--modules" in sys.argv:
+        idx = sys.argv.index("--modules")
+        if idx + 1 < len(sys.argv):
+            module_filter = parse_module_filter(sys.argv[idx + 1])
+            log.info(f"Module filter: {sorted(module_filter)}")
+
     AUDIO_DIR.mkdir(exist_ok=True)
 
     session = requests.Session()
@@ -185,7 +206,10 @@ def main():
     skipped = 0
     failed = 0
 
-    for mod in modules:
+    for mod_idx, mod in enumerate(modules, 1):
+        if module_filter and mod_idx not in module_filter:
+            log.info(f"  Skipping module {mod_idx}: {mod['name']}")
+            continue
         lectures = discover_lectures(session, mod)
         module_entry = {
             "name": mod["name"],
diff --git a/run.bat b/run.bat
index 1a65c54..24bbe5a 100644
--- a/run.bat
+++ b/run.bat
@@ -265,7 +265,12 @@ echo      Done.
 echo.
 echo [3/4] Downloading audio files...
 echo ============================================================
-.venv\Scripts\python download.py
+if "%~1"=="" (
+    .venv\Scripts\python download.py
+) else (
+    echo Modules filter: %~1
+    .venv\Scripts\python download.py --modules %~1
+)
 if errorlevel 1 (
     echo.
     echo WARNING: Some downloads failed. Check download_errors.log