diff --git a/package.json b/package.json
index 23aabca..c2ef9d4 100644
--- a/package.json
+++ b/package.json
@@ -18,6 +18,7 @@
   },
   "tree-sitter": [
     {
+      "first-line-regex": "^#!.*\\bnix-shell\\b.*$",
       "injection-regex": "^(nix[-_]?shell)$",
       "scope": "source.nix_shell"
     }