diff --git a/pkgs/development/interpreters/tcl/generic.nix b/pkgs/development/interpreters/tcl/generic.nix
index f5d3e863361d..2a224f3fb30f 100644
--- a/pkgs/development/interpreters/tcl/generic.nix
+++ b/pkgs/development/interpreters/tcl/generic.nix
@@ -200,6 +200,7 @@ stdenv.mkDerivation (finalAttrs: {
     homepage = "https://www.tcl.tk/";
     license = lib.licenses.tcltk;
     platforms = lib.platforms.all;
+    mainProgram = "tclsh";
     maintainers = with lib.maintainers; [ agbrooks ];
   };