diff --git a/lib/linguist/languages.yml b/lib/linguist/languages.yml
index adfce612..2d0b3a56 100644
--- a/lib/linguist/languages.yml
+++ b/lib/linguist/languages.yml
@@ -1373,6 +1373,7 @@ XML:
   - .tmLanguage
   - .tmPreferences
   - .tmSnippet
+  - .tmTheme
   - .tml
   - .ui
   - .vxml