diff --git a/pkgs/development/python-modules/pythran/default.nix b/pkgs/development/python-modules/pythran/default.nix
index 7a55b2003ab7..25f21b2fa506 100644
--- a/pkgs/development/python-modules/pythran/default.nix
+++ b/pkgs/development/python-modules/pythran/default.nix
@@ -10,6 +10,7 @@
 , six
 , numpy
 , beniget
+, xsimd
 , isPy3k
 , substituteAll
 }:
@@ -36,6 +37,12 @@ in buildPythonPackage rec {
     })
   ];
 
+  # xsimd: unvendor this header-only C++ lib
+  postPatch = ''
+    rm -r third_party/xsimd
+    ln -s '${lib.getDev xsimd}'/include/xsimd third_party/
+  '';
+
   propagatedBuildInputs = [
     ply
     networkx