diff --git a/src/Illuminate/Routing/SortedMiddleware.php b/src/Illuminate/Routing/SortedMiddleware.php
index 1e3cf797a2c4..ec881c3d77ba 100644
--- a/src/Illuminate/Routing/SortedMiddleware.php
+++ b/src/Illuminate/Routing/SortedMiddleware.php
@@ -65,7 +65,7 @@ protected function sortMiddleware($priorityMap, $middlewares)
             }
         }
 
-        return $middlewares;
+        return array_values(array_unique($middlewares, SORT_REGULAR));
     }
 
     /**
diff --git a/tests/Routing/RoutingSortedMiddlewareTest.php b/tests/Routing/RoutingSortedMiddlewareTest.php
index 4f3d74655899..baa84c8176f0 100644
--- a/tests/Routing/RoutingSortedMiddlewareTest.php
+++ b/tests/Routing/RoutingSortedMiddlewareTest.php
@@ -18,8 +18,7 @@ public function testMiddlewareCanBeSortedByPriority()
             'Something',
             'Something',
             'Second',
-            'Something',
-            'Something',
+            'Otherthing',
             'First:api',
             'Third:foo',
             'First:foo,bar',
@@ -28,16 +27,11 @@ public function testMiddlewareCanBeSortedByPriority()
         ];
 
         $expected = [
-            'Something',
-            'Something',
-            'Something',
             'Something',
             'First:api',
             'First:foo,bar',
             'Second',
-            'Something',
-            'Something',
-            'Second',
+            'Otherthing',
             'Third:foo',
             'Third',
         ];