diff --git a/pkgs/applications/networking/mailreaders/notmuch/default.nix b/pkgs/applications/networking/mailreaders/notmuch/default.nix
index 9db9782e2ed..c2c5d18e2f0 100644
--- a/pkgs/applications/networking/mailreaders/notmuch/default.nix
+++ b/pkgs/applications/networking/mailreaders/notmuch/default.nix
@@ -56,6 +56,8 @@ stdenv.mkDerivation rec {
     done
   '';
 
+  configureFlags = [ "--zshcompletiondir=$(out)/share/zsh/site-functions" ];
+
   # Notmuch doesn't use autoconf and consequently doesn't tag --bindir and
   # friends
   setOutputFlags = false;