diff --git a/pkgs/applications/networking/msmtp/default.nix b/pkgs/applications/networking/msmtp/default.nix
index 174fa5e9d9f5..e68e8f8fe96b 100644
--- a/pkgs/applications/networking/msmtp/default.nix
+++ b/pkgs/applications/networking/msmtp/default.nix
@@ -40,6 +40,7 @@ let
     license = licenses.gpl3Plus;
     maintainers = with maintainers; [ peterhoeg ];
     platforms = platforms.unix;
+    mainProgram = "msmtp";
   };
 
   binaries = stdenv.mkDerivation {