diff --git a/lodash.js b/lodash.js
index 86b22c9b1..d022e6ccb 100644
--- a/lodash.js
+++ b/lodash.js
@@ -6271,10 +6271,13 @@
      * @returns {boolean} Returns `true` if `value` is a valid index, else `false`.
      */
     function isIndex(value, length) {
-      length = length == null ? MAX_SAFE_INTEGER : length;
+      var type = typeof value
+      length = length == null ? MAX_SAFE_INTEGER : length
+
       return !!length &&
-        (typeof value == 'number' || reIsUint.test(value)) &&
-        (value > -1 && value % 1 == 0 && value < length);
+        (type == 'number' ||
+          (type != 'symbol' && reIsUint.test(value))) &&
+              (value > -1 && value % 1 == 0 && value < length)
     }
 
     /**