diff --git a/README.md b/README.md
index 22b6993cc..6b084652c 100644
--- a/README.md
+++ b/README.md
@@ -52,7 +52,7 @@ Full cli option list:
        -j, --json                    force jison to expect a grammar in JSON format
        -o FILE, --outfile FILE       Filename and base module name of the generated parser
        -t, --debug                   Debug mode
-       -m TYPE, --module-type TYPE   The type of module to generate (commonjs, amd, js)
+       -m TYPE, --module-type TYPE   The type of module to generate (**es**, commonjs, amd, js)
        -p TYPE, --parser-type TYPE   The type of algorithm to use for the parser (lr0, slr, lalr, lr)
        -V, --version                 print version and exit
 
diff --git a/lib/cli.js b/lib/cli.js
index 338a23827..aa5970489 100755
--- a/lib/cli.js
+++ b/lib/cli.js
@@ -35,9 +35,9 @@ function getCommandlineOptions () {
         .option('module-type', {
             abbr : 'm',
         default:
-            'commonjs',
+            'es',
             metavar : 'TYPE',
-            help : 'The type of module to generate (commonjs, amd, js)'
+            help : 'The type of module to generate (es, commonjs, amd, js)'
         })
         .option('parser-type', {
             abbr : 'p',