diff --git a/syntaxes/flix.tmLanguage.json b/syntaxes/flix.tmLanguage.json
index 0621c0a..e848a41 100644
--- a/syntaxes/flix.tmLanguage.json
+++ b/syntaxes/flix.tmLanguage.json
@@ -171,6 +171,10 @@
           "name": "keyword.use.flix",
           "match": "\\b(use)\\b"
         },
+        {
+          "name": "keyword.mut.flix",
+          "match": "\\b(mut)\\b"
+        },
         {
           "name": "keyword.symbols.flix",
           "match": "(\\->|~>|<\\-|=>)"