diff --git a/otto/main.go b/otto/main.go
index 96820c2..6f4d0fe 100644
--- a/otto/main.go
+++ b/otto/main.go
@@ -6,8 +6,11 @@ import (
 	"io/ioutil"
 	"os"
 	"github.com/robertkrimen/otto"
+	"github.com/robertkrimen/otto/underscore"
 )
 
+var underscoreFlag *bool = flag.Bool("underscore", true, "Load underscore into the runtime environment")
+
 func main() {
 	flag.Parse()
 	var script []byte
@@ -26,6 +29,9 @@ func main() {
 			os.Exit(64)
 		}
 	}
+	if !*underscoreFlag {
+		underscore.Disable()
+	}
 	Otto := otto.New()
 	_, err = Otto.Run(string(script))
 	if err != nil {