diff --git a/lib/systems/default.nix b/lib/systems/default.nix
index e31a8e65f2a..4edcbeb36f1 100644
--- a/lib/systems/default.nix
+++ b/lib/systems/default.nix
@@ -124,6 +124,8 @@ rec {
         then "${qemu-user}/bin/qemu-${final.qemuArch}"
         else if final.isWasi
         then "${pkgs.wasmtime}/bin/wasmtime"
+        else if final.isMmix
+        then "${pkgs.mmixware}/bin/mmix"
         else throw "Don't know how to run ${final.config} executables.";
 
     } // mapAttrs (n: v: v final.parsed) inspect.predicates