diff --git a/lib/rules/jsx-no-duplicate-props.js b/lib/rules/jsx-no-duplicate-props.js
index 092f0597b1..54c9db4ef0 100644
--- a/lib/rules/jsx-no-duplicate-props.js
+++ b/lib/rules/jsx-no-duplicate-props.js
@@ -46,7 +46,7 @@ module.exports = {
 
           var name = decl.name.name;
 
-          if (ignoreCase) {
+          if (ignoreCase && typeof name === 'string') {
             name = name.toLowerCase();
           }