diff --git a/pkgs/development/ruby-modules/gem-config/default.nix b/pkgs/development/ruby-modules/gem-config/default.nix
index 74ea4c823deb..ce0daf38dabc 100644
--- a/pkgs/development/ruby-modules/gem-config/default.nix
+++ b/pkgs/development/ruby-modules/gem-config/default.nix
@@ -198,7 +198,7 @@ in
   };
 
   ruby-libvirt = attrs: {
-    buildInputs = [ libvirt ];
+    buildInputs = [ libvirt pkgconfig ];
     buildFlags = [
       "--with-libvirt-include=${libvirt}/include"
       "--with-libvirt-lib=${libvirt}/lib"