diff --git a/shells/ruby.nix b/shells/ruby.nix
index 1cc8133..04289cf 100644
--- a/shells/ruby.nix
+++ b/shells/ruby.nix
@@ -6,6 +6,6 @@
   shellHook = ''
     export BUNDLE_HOME="$PWD/.nix/bundle"
     export GEM_HOME="$PWD/.nix/gem"
-    export PATH="GEM_HOME/bin:$PATH"
+    export PATH="$GEM_HOME/bin:$PATH"
   '';
 }