diff --git a/src/Hydrator/NamingStrategy/UnderscoreNamingStrategy.php b/src/Hydrator/NamingStrategy/UnderscoreNamingStrategy.php
index c6eceb531..52dc27677 100644
--- a/src/Hydrator/NamingStrategy/UnderscoreNamingStrategy.php
+++ b/src/Hydrator/NamingStrategy/UnderscoreNamingStrategy.php
@@ -13,9 +13,15 @@
 
 class UnderscoreNamingStrategy implements NamingStrategyInterface
 {
+    /**
+     * @var FilterChain|null
+     */
     protected static $camelCaseToUnderscoreFilter;
 
-    protected static $underscoreToCamelCaseFilter;
+    /**
+     * @var FilterChain|null
+     */
+    protected static $underscoreToStudlyCaseFilter;
 
     /**
      * Remove underscores and capitalize letters
@@ -25,7 +31,7 @@ class UnderscoreNamingStrategy implements NamingStrategyInterface
      */
     public function hydrate($name)
     {
-        return lcfirst($this->getUnderscoreToCamelCaseFilter()->filter($name));
+        return $this->getUnderscoreToStudlyCaseFilter()->filter($name);
     }
 
     /**
@@ -42,16 +48,17 @@ public function extract($name)
     /**
      * @return FilterChain
      */
-    protected function getUnderscoreToCamelCaseFilter()
+    protected function getUnderscoreToStudlyCaseFilter()
     {
-        if (static::$underscoreToCamelCaseFilter instanceof FilterChain) {
-            return static::$underscoreToCamelCaseFilter;
+        if (static::$underscoreToStudlyCaseFilter instanceof FilterChain) {
+            return static::$underscoreToStudlyCaseFilter;
         }
 
         $filter = new FilterChain();
-        $filter->attachByName('WordUnderscoreToCamelCase');
-        static::$underscoreToCamelCaseFilter = $filter;
-        return $filter;
+
+        $filter->attachByName('WordUnderscoreToStudlyCase');
+
+        return static::$underscoreToStudlyCaseFilter = $filter;
     }
 
     /**
@@ -64,9 +71,10 @@ protected function getCamelCaseToUnderscoreFilter()
         }
 
         $filter = new FilterChain();
+
         $filter->attachByName('WordCamelCaseToUnderscore');
         $filter->attachByName('StringToLower');
-        static::$camelCaseToUnderscoreFilter = $filter;
-        return $filter;
+
+        return static::$camelCaseToUnderscoreFilter = $filter;
     }
 }
diff --git a/test/Hydrator/NamingStrategy/UnderscoreNamingStrategyTest.php b/test/Hydrator/NamingStrategy/UnderscoreNamingStrategyTest.php
index 2162ef5bd..ad3a790d0 100644
--- a/test/Hydrator/NamingStrategy/UnderscoreNamingStrategyTest.php
+++ b/test/Hydrator/NamingStrategy/UnderscoreNamingStrategyTest.php
@@ -29,4 +29,15 @@ public function testNameExtractsToUnderscore()
         $strategy = new UnderscoreNamingStrategy();
         $this->assertEquals('foo_bar_baz', $strategy->extract('fooBarBaz'));
     }
+
+    /**
+     * @group 6422
+     * @group 6420
+     */
+    public function testNameHydratesToStudlyCaps()
+    {
+        $strategy = new UnderscoreNamingStrategy();
+
+        $this->assertEquals('fooBarBaz', $strategy->hydrate('Foo_Bar_Baz'));
+    }
 }