diff --git a/modules/videos/downloader.py b/modules/videos/downloader.py
index 6204a1e9..48e91aa2 100755
--- a/modules/videos/downloader.py
+++ b/modules/videos/downloader.py
@@ -994,14 +994,16 @@ class VideoDownloader(Downloader, ABC):
         new_files = []
         for file in files:
             suffix = file.name[len(video_stem):]
-            if suffix.endswith('.vtt'):
+            if suffix.endswith('.vtt') or suffix.endswith('.srt'):
                 _, normal_suffix = split_path_stem_and_suffix(file.name)
                 if suffix != normal_suffix:
                     # Video captions file has extra characters in the suffix from yt-dlp.
                     # Example:  .en-uYU-mmqFLq8.vtt -> .en.vtt
-                    lang, _, suffix = VTT_SUFFIX_PARSER.match(suffix.strip()).groups()
-                    suffix = f'.{lang}.{suffix}'
-                    file = file.rename(video_path.with_suffix(suffix))
+                    match = VTT_SUFFIX_PARSER.match(suffix.strip())
+                    if match:
+                        lang, _, suffix = match.groups()
+                        suffix = f'.{lang}.{suffix}'
+                        file = file.rename(video_path.with_suffix(suffix))
             new_files.append(file)
 
         return new_files
diff --git a/modules/videos/test/test_downloader.py b/modules/videos/test/test_downloader.py
index 44314245..e1c6c989 100644
--- a/modules/videos/test/test_downloader.py
+++ b/modules/videos/test/test_downloader.py
@@ -653,6 +653,12 @@ def test_normalize_video_file_names(test_directory, video_download_manager):
     }
     assert not vtt.exists()
 
+    # VTT suffix that does not match expected pattern is left unchanged.
+    vtt = test_directory / 'video.unknown_format.vtt'
+    vtt.touch()
+    assert set(downloader.normalize_video_file_names(mp4, [mp4, vtt, info_json])) == {mp4, vtt, info_json}
+    assert vtt.exists()
+
 
 @pytest.mark.asyncio
 async def test_channel_downloader_sets_collection_id(test_session, channel_factory, mock_video_extract_info,