diff --git a/lib/linguist/languages.yml b/lib/linguist/languages.yml
index b987eed8..21021ea9 100644
--- a/lib/linguist/languages.yml
+++ b/lib/linguist/languages.yml
@@ -733,6 +733,7 @@ Perl:
   - .perl
   - .ph
   - .pl
+  - .plx
   - .pm
   - .pod
   - .psgi