diff --git a/src/Modal.js b/src/Modal.js
index ed4db06466..7241f39002 100644
--- a/src/Modal.js
+++ b/src/Modal.js
@@ -163,7 +163,7 @@ const Modal = React.createClass({
     let modal = (
       <Dialog {...props}
         ref={this._setDialogRef}
-        className={classNames({ in: show && !animation })}
+        className={classNames(this.props.className, { in: show && !animation })}
         onClick={backdrop === true ? this.handleBackdropClick : null}
       >
         { this.renderContent() }
diff --git a/test/ModalSpec.js b/test/ModalSpec.js
index 99affa0485..9d5ceb0178 100644
--- a/test/ModalSpec.js
+++ b/test/ModalSpec.js
@@ -130,6 +130,19 @@ describe('Modal', function () {
     ReactTestUtils.Simulate.click(button);
   });
 
+  it('Should pass className to the dialog', function () {
+    let noOp = function () {};
+    let instance = render(
+      <Modal show className='mymodal' onHide={noOp}>
+        <strong>Message</strong>
+      </Modal>
+    , mountPoint);
+
+    let dialog = React.findDOMNode(instance.refs.dialog);
+
+    assert.ok(dialog.className.match(/\bmymodal\b/));
+  });
+
   it('Should use bsClass on the dialog', function () {
     let noOp = function () {};
     let instance = render(