diff --git a/src/Instantiator/Instantiator.php b/src/Instantiator/Instantiator.php
index f1ab8c0..48ee5d9 100644
--- a/src/Instantiator/Instantiator.php
+++ b/src/Instantiator/Instantiator.php
@@ -113,6 +113,29 @@ public function buildFactory($className)
         };
     }
 
+    /**
+     * Checks if a class is cloneable
+     *
+     * @internal
+     * @private
+     *
+     * This method is only exposed as public because of PHP 5.3 compatibility. Do not
+     * use this method in your own code
+     *
+     * @param ReflectionClass $class
+     *
+     * @return bool
+     */
+    public function isSafeToClone(ReflectionClass $class)
+    {
+        if (method_exists($class, 'isCloneable') && ! $class->isCloneable()) {
+            return false;
+        }
+
+        // not cloneable if it implements `__clone`, as we want to avoid calling it
+        return ! $class->hasMethod('__clone');
+    }
+
     /**
      * @param string $className
      *
@@ -258,16 +281,15 @@ private function getInstantiatorsMap()
     private function getCloneablesMap()
     {
         $cachedInstantiators = $this->getInstantiatorsMap();
+        $that                = $this;
 
         return self::$cachedCloneables = self::$cachedCloneables
-            ?: new CallbackLazyMap(function ($className) use ($cachedInstantiators) {
+            ?: new CallbackLazyMap(function ($className) use ($cachedInstantiators, $that) {
                 /* @var $factory Closure */
                 $factory    = $cachedInstantiators->$className;
                 $instance   = $factory();
-                $reflection = new ReflectionClass($instance);
 
-                // not cloneable if it implements `__clone`, as we want to avoid calling it
-                if ($reflection->hasMethod('__clone')) {
+                if (! $that->isSafeToClone(new ReflectionClass($className))) {
                     return null;
                 }
 
diff --git a/tests/InstantiatorTest/InstantiatorTest.php b/tests/InstantiatorTest/InstantiatorTest.php
index 18fe298..c17172f 100644
--- a/tests/InstantiatorTest/InstantiatorTest.php
+++ b/tests/InstantiatorTest/InstantiatorTest.php
@@ -169,6 +169,7 @@ public function getInstantiableClasses()
             array('InstantiatorTestAsset\\SimpleSerializableAsset'),
             array('InstantiatorTestAsset\\PharExceptionAsset'),
             array('InstantiatorTestAsset\\UnCloneableAsset'),
+            array('InstantiatorTestAsset\\XMLReaderAsset'),
         );
 
         if (\PHP_VERSION_ID === 50429 || \PHP_VERSION_ID === 50513) {
diff --git a/tests/InstantiatorTestAsset/XMLReaderAsset.php b/tests/InstantiatorTestAsset/XMLReaderAsset.php
new file mode 100644
index 0000000..b42f0f2
--- /dev/null
+++ b/tests/InstantiatorTestAsset/XMLReaderAsset.php
@@ -0,0 +1,42 @@
+<?php
+/*
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * This software consists of voluntary contributions made by many individuals
+ * and is licensed under the MIT license. For more information, see
+ * <http://www.doctrine-project.org>.
+ */
+
+namespace InstantiatorTestAsset;
+
+use BadMethodCallException;
+use XMLReader;
+
+/**
+ * Test asset that extends an internal PHP class
+ *
+ * @author Dave Marshall <dave@atst.io>
+ * @link https://github.com/doctrine/instantiator/pull/8
+ */
+class XMLReaderAsset extends XMLReader
+{
+    /**
+     * Constructor - should not be called
+     *
+     * @throws BadMethodCallException
+     */
+    public function __construct()
+    {
+        throw new BadMethodCallException('Not supposed to be called!');
+    }
+}