diff --git a/lib/linguist/languages.yml b/lib/linguist/languages.yml
index 11e7a62d..d3727ba5 100644
--- a/lib/linguist/languages.yml
+++ b/lib/linguist/languages.yml
@@ -1430,6 +1430,7 @@ XML:
   - .wxi
   - .wxl
   - .wxs
+  - .x3d
   - .xaml
   - .xlf
   - .xliff