diff --git a/lib/Github/Api/AbstractApi.php b/lib/Github/Api/AbstractApi.php
index a9204787659..d4d501ed3ec 100644
--- a/lib/Github/Api/AbstractApi.php
+++ b/lib/Github/Api/AbstractApi.php
@@ -103,7 +103,7 @@ protected function get($path, array $parameters = [], array $requestHeaders = []
         }
 
         if (count($parameters) > 0) {
-            $path .= '?'.http_build_query($parameters);
+            $path .= '?'.http_build_query($parameters, '', '&', PHP_QUERY_RFC3986);
         }
 
         $response = $this->client->getHttpClient()->get($path, $requestHeaders);
@@ -126,7 +126,7 @@ protected function head($path, array $parameters = [], array $requestHeaders = [
             unset($parameters['ref']);
         }
 
-        return $this->client->getHttpClient()->head($path.'?'.http_build_query($parameters), $requestHeaders);
+        return $this->client->getHttpClient()->head($path.'?'.http_build_query($parameters, '', '&', PHP_QUERY_RFC3986), $requestHeaders);
     }
 
     /**
diff --git a/lib/Github/HttpClient/Plugin/Authentication.php b/lib/Github/HttpClient/Plugin/Authentication.php
index a70593b8791..669fb1d8965 100644
--- a/lib/Github/HttpClient/Plugin/Authentication.php
+++ b/lib/Github/HttpClient/Plugin/Authentication.php
@@ -69,7 +69,7 @@ public function doHandleRequest(RequestInterface $request, callable $next, calla
                 ];
 
                 $query .= empty($query) ? '' : '&';
-                $query .= utf8_encode(http_build_query($parameters, '', '&'));
+                $query .= utf8_encode(http_build_query($parameters, '', '&', PHP_QUERY_RFC3986));
 
                 $uri = $uri->withQuery($query);
                 $request = $request->withUri($uri);