diff --git a/pkgs/development/ruby-modules/gem-config/default.nix b/pkgs/development/ruby-modules/gem-config/default.nix
index 31f930ef1086..ef8aa67d3503 100644
--- a/pkgs/development/ruby-modules/gem-config/default.nix
+++ b/pkgs/development/ruby-modules/gem-config/default.nix
@@ -42,6 +42,7 @@
   xapian,
   gpgme,
   util-linux,
+  readline,
   tzdata,
   icu,
   libffi,
@@ -962,6 +963,10 @@ in
     ];
   };
 
+  readline-ext = attrs: {
+    buildInputs = [ readline ];
+  };
+
   rest-client = attrs: {
     meta.mainProgram = "restclient";
   };