diff --git a/packages/material-ui-utils/src/refType.js b/packages/material-ui-utils/src/refType.js
index cf0dda460e5fe6..8e6317b888ca0c 100644
--- a/packages/material-ui-utils/src/refType.js
+++ b/packages/material-ui-utils/src/refType.js
@@ -1,5 +1,5 @@
 import PropTypes from 'prop-types';
 
-const refType = PropTypes.oneOfType([PropTypes.func, PropTypes.PropTypes.object]);
+const refType = PropTypes.oneOfType([PropTypes.func, PropTypes.object]);
 
 export default refType;