diff --git a/pkgs/top-level/python-packages.nix b/pkgs/top-level/python-packages.nix
index 8ec9e1a0896..5403bc45ab4 100644
--- a/pkgs/top-level/python-packages.nix
+++ b/pkgs/top-level/python-packages.nix
@@ -765,7 +765,7 @@ let pythonPackages = python.modules // rec {
 
     doCheck = false;
 
-    buildInputs = [ dateutil numpy pkgs.freetype pkgs.libpng pkgs.pkgconfig pkgs.tcl pkgs.tk pkgs.xlibs.libX11 ];
+    propagatedBuildInputs = [ dateutil numpy pkgs.freetype pkgs.libpng pkgs.pkgconfig pkgs.tcl pkgs.tk pkgs.xlibs.libX11 ];
 
     meta = {
       description = "python plotting library, making publication quality plots";