diff --git a/pkgs/applications/networking/mailreaders/thunderbird/default.nix b/pkgs/applications/networking/mailreaders/thunderbird/default.nix
index c4a2eed899bd..94d1d08b9e47 100644
--- a/pkgs/applications/networking/mailreaders/thunderbird/default.nix
+++ b/pkgs/applications/networking/mailreaders/thunderbird/default.nix
@@ -22,7 +22,7 @@ stdenv.mkDerivation {
     sha1 = "4bcbb33f0b3ea050e805723680b5669d80438812";
   };
 
-  enableParallelBuilding = false;
+  enableParallelBuilding = true;
 
   buildInputs =
     [ pkgconfig perl python zip unzip bzip2 gtk dbus_glib alsaLib libIDL nspr