diff --git a/pkgs/development/python-modules/notmuch2/default.nix b/pkgs/development/python-modules/notmuch2/default.nix
index b8ed00ca2579..9bb930d6cfa4 100644
--- a/pkgs/development/python-modules/notmuch2/default.nix
+++ b/pkgs/development/python-modules/notmuch2/default.nix
@@ -16,9 +16,11 @@ buildPythonPackage {
     cffi
   ];
   buildInputs = [
-    python notmuch cffi
+    python notmuch
   ];
 
+  propagatedBuildInputs = [ cffi ];
+
   # since notmuch 0.35, this package expects _notmuch_config.py that is
   # generated by notmuch's configure script. We write one which references our
   # built libraries.