diff --git a/pkgs/tools/misc/expect/default.nix b/pkgs/tools/misc/expect/default.nix
index bd876371ae2..19ab5158a65 100644
--- a/pkgs/tools/misc/expect/default.nix
+++ b/pkgs/tools/misc/expect/default.nix
@@ -41,6 +41,7 @@ tcl.mkTclDerivation rec {
     homepage = "https://expect.sourceforge.net/";
     license = licenses.publicDomain;
     platforms = platforms.unix;
+    mainProgram = "expect";
     maintainers = with maintainers; [ SuperSandro2000 ];
   };
 }