diff --git a/conformance/autoload.php b/conformance/autoload.php
new file mode 100644
index 0000000..0f49aec
--- /dev/null
+++ b/conformance/autoload.php
@@ -0,0 +1,21 @@
+<?php
+
+define("GOOGLE_INTERNAL_NAMESPACE", "Google\\Protobuf\\Internal\\");
+define("GOOGLE_NAMESPACE", "Google\\Protobuf\\");
+define("GOOGLE_GPBMETADATA_NAMESPACE", "GPBMetadata\\Google\\Protobuf\\");
+
+function protobuf_autoloader_impl($class, $prefix) {
+    $length = strlen($prefix);
+    if ((substr($class, 0, $length) === $prefix)) {
+        $path = '../php/src/' . implode('/', array_map('ucwords', explode('\\', $class))) . '.php';
+        include_once $path;
+    }
+}
+
+function protobuf_autoloader($class) {
+    protobuf_autoloader_impl($class, GOOGLE_INTERNAL_NAMESPACE);
+    protobuf_autoloader_impl($class, GOOGLE_NAMESPACE);
+    protobuf_autoloader_impl($class, GOOGLE_GPBMETADATA_NAMESPACE);
+}
+
+spl_autoload_register('protobuf_autoloader');