diff --git a/pkgs/development/compilers/vala/default.nix b/pkgs/development/compilers/vala/default.nix
index 83444b53f19..6a020e11a4b 100644
--- a/pkgs/development/compilers/vala/default.nix
+++ b/pkgs/development/compilers/vala/default.nix
@@ -77,6 +77,7 @@ in rec {
     major   = "0.40";
     minor   = "0";
     sha256  = "0wcfljl55a9qvslfcc4sf76wdpwgn83n96b7fgb7r49ib35qz20m";
+    extraNativeBuildInputs = stdenv.lib.optionals stdenv.isDarwin [ expat ];
     extraBuildInputs = [ graphviz ];
   };