diff --git a/elm-io.sh b/elm-io.sh
index 5907a58..69bee7a 100755
--- a/elm-io.sh
+++ b/elm-io.sh
@@ -1,14 +1,18 @@
 #!/usr/bin/env bash
-if [ "$#" -ne 2 ]; then
-    echo "Usage: $0 <generated-js-file> <output-file>"
+if [ "$#" = 3 ]; then
+    MAIN_MODULE=$3
+elif [ "$#" = 2 ]; then
+    MAIN_MODULE=Main
+else
+    echo "Usage: $0 <generated-js-file> <output-file> [<Main>]"
     exit 1
 fi
 
 read -d '' handler <<- EOF
 (function(){
     if (typeof Elm === "undefined") { throw "elm-io config error: Elm is not defined. Make sure you call elm-io with a real Elm output file"}
-    if (typeof Elm.Main === "undefined" ) { throw "Elm.Main is not defined, make sure your module is named Main." };
-    var worker = Elm.worker(Elm.Main);
+    if (typeof Elm.${MAIN_MODULE} === "undefined" ) { throw "Elm.${MAIN_MODULE} is not defined, make sure your module is named Main." };
+    var worker = Elm.worker(Elm.${MAIN_MODULE});
 })();
 EOF