diff --git a/src/RequestBridge.php b/src/RequestBridge.php
index 8c3c383..51fb4d7 100644
--- a/src/RequestBridge.php
+++ b/src/RequestBridge.php
@@ -2,6 +2,7 @@
 namespace Chadicus\Slim\OAuth2\Http;
 
 use Psr\Http\Message\ServerRequestInterface;
+use Psr\Http\Message\UploadedFileInterface;
 use OAuth2;
 
 /**
@@ -69,23 +70,36 @@ private static function cleanupHeaders(array $uncleanHeaders = [])
     /**
      * Convert a PSR-7 uploaded files structure to a $_FILES structure.
      *
-     * @param \Psr\Http\Message\UploadedFileInterface[] $uploadedFiles Array of file objects.
+     * @param array $uploadedFiles Array of file objects.
      *
      * @return array
      */
     private static function convertUploadedFiles(array $uploadedFiles)
     {
         $files = [];
-        foreach ($uploadedFiles as $name => $upload) {
-            $files[$name] = [
-                'name' => $upload->getClientFilename(),
-                'type' => $upload->getClientMediaType(),
-                'size' => $upload->getSize(),
-                'tmp_name' => $upload->getStream()->getMetadata('uri'),
-                'error' => $upload->getError(),
-            ];
+        foreach ($uploadedFiles as $name => $uploadedFile) {
+            if (!is_array($uploadedFile)) {
+                $files[$name] = self::convertUploadedFile($uploadedFile);
+                continue;
+            }
+
+            $files[$name] = [];
+            foreach ($uploadedFile as $file) {
+                $files[$name][] = self::convertUploadedFile($file);
+            }
         }
 
         return $files;
     }
+
+    private static function convertUploadedFile(UploadedFileInterface $uploadedFile)
+    {
+        return [
+            'name' => $uploadedFile->getClientFilename(),
+            'type' => $uploadedFile->getClientMediaType(),
+            'size' => $uploadedFile->getSize(),
+            'tmp_name' => $uploadedFile->getStream()->getMetadata('uri'),
+            'error' => $uploadedFile->getError(),
+        ];
+    }
 }
diff --git a/tests/RequestBridgeTest.php b/tests/RequestBridgeTest.php
index 01ca5a6..2a35f61 100644
--- a/tests/RequestBridgeTest.php
+++ b/tests/RequestBridgeTest.php
@@ -177,4 +177,57 @@ public function toOAuth2BodyContentsOfRequestPreserved()
         $this->assertSame('foo', $psr7Request->getBody()->getContents());
         $this->assertSame('foo', $oauth2Request->getContent());
     }
+
+    /**
+     * @test
+     * @covers ::toOAuth2
+     *
+     * @return void
+     */
+    public function toOAuth2WithMultipleFiles()
+    {
+        $files = [
+            'multi' => [
+                new UploadedFile(
+                    __FILE__,
+                    100,
+                    UPLOAD_ERR_OK,
+                    'foo1.txt',
+                    'text/plain'
+                ),
+                new UploadedFile(
+                    __FILE__,
+                    100,
+                    UPLOAD_ERR_OK,
+                    'foo2.txt',
+                    'text/plain'
+                ),
+            ],
+        ];
+
+        $psr7Request = (new ServerRequest())->withUploadedFiles($files);
+        $oauth2Request = RequestBridge::toOauth2($psr7Request);
+
+        $this->assertSame(
+            [
+                'multi' => [
+                    [
+                        'name' => 'foo1.txt',
+                        'type' => 'text/plain',
+                        'size' => 100,
+                        'tmp_name' => __FILE__,
+                        'error' => UPLOAD_ERR_OK,
+                    ],
+                    [
+                        'name' => 'foo2.txt',
+                        'type' => 'text/plain',
+                        'size' => 100,
+                        'tmp_name' => __FILE__,
+                        'error' => UPLOAD_ERR_OK,
+                    ],
+                ],
+            ],
+            $oauth2Request->files
+        );
+    }
 }