diff --git a/lib/parse.js b/lib/parse.js
index 9adad86e..e3c382ca 100644
--- a/lib/parse.js
+++ b/lib/parse.js
@@ -60,6 +60,8 @@ var charsetSentinel = 'utf8=%E2%9C%93'; // encodeURIComponent('✓')
 var parseValues = function parseQueryStringValues(str, options) {
     var obj = { __proto__: null };
 
+    var keysByRoot = options.duplicates === 'last' ? { __proto__: null } : undefined;
+
     var cleanStr = options.ignoreQueryPrefix ? str.replace(/^\?/, '') : str;
     cleanStr = cleanStr.replace(/%5B/gi, '[').replace(/%5D/gi, ']');
 
@@ -131,8 +133,25 @@ var parseValues = function parseQueryStringValues(str, options) {
         }
 
         if (key !== null) {
+            if (options.duplicates === 'last') {
+                var keyIsArray = key.indexOf('[') !== -1;
+                var root = keyIsArray ? key.split('[')[0] : key;
+                var existingKeys = keysByRoot[root];
+                if (!existingKeys) {
+                    keysByRoot[root] = [key];
+                } else if (existingKeys[0].indexOf('[') !== -1 === keyIsArray) {
+                    existingKeys.push(key);
+                } else {
+                    for (var j = 0; j < existingKeys.length; j++) {
+                        delete obj[existingKeys[j]];
+                    }
+                    keysByRoot[root] = [key];
+                }
+            }
+
             var existing = has.call(obj, key);
-            if (existing && options.duplicates === 'combine') {
+            if (existing && (options.duplicates === 'combine'
+                || (options.duplicates === 'last' && key !== null && key.indexOf('[]') !== -1))) {
                 obj[key] = utils.combine(obj[key], val);
             } else if (!existing || options.duplicates === 'last') {
                 obj[key] = val;