diff --git a/core/lib/Drupal/Core/Utility/UnroutedUrlAssembler.php b/core/lib/Drupal/Core/Utility/UnroutedUrlAssembler.php
index 2569ee4adbaba186634f2a542674a1cd40806c9e..5e50f5e2b30617633100d69e24f1c5f11e2410de 100644
--- a/core/lib/Drupal/Core/Utility/UnroutedUrlAssembler.php
+++ b/core/lib/Drupal/Core/Utility/UnroutedUrlAssembler.php
@@ -78,7 +78,6 @@ protected function buildExternalUrl($uri, array $options = [], $collect_bubbleab
     $options += ['query' => []];
 
     $options['query'] = NestedArray::mergeDeep($parsed['query'], $options['query']);
-    ksort($options['query']);
 
     if ($parsed['fragment'] && !$options['fragment']) {
       $options['fragment'] = '#' . $parsed['fragment'];
diff --git a/core/modules/system/tests/src/Functional/Common/UrlTest.php b/core/modules/system/tests/src/Functional/Common/UrlTest.php
index 8e4d7b121c5852a7d7ca65ebf85d2350f7734d9e..362868c3178321f939f803507a9a268ddde73d6e 100644
--- a/core/modules/system/tests/src/Functional/Common/UrlTest.php
+++ b/core/modules/system/tests/src/Functional/Common/UrlTest.php
@@ -314,7 +314,7 @@ public function testExternalUrls() {
     $url = $test_url . '?drupal=awesome';
     $query = ['awesome' => 'drupal'];
     $result = Url::fromUri($url, ['query' => $query])->toString();
-    $this->assertEqual('https://www.drupal.org/?awesome=drupal&drupal=awesome', $result);
+    $this->assertEqual('https://www.drupal.org/?drupal=awesome&awesome=drupal', $result);
   }
 
 }
diff --git a/core/tests/Drupal/Tests/Core/Utility/UnroutedUrlAssemblerTest.php b/core/tests/Drupal/Tests/Core/Utility/UnroutedUrlAssemblerTest.php
index 70b3880f4c1df8c7eebf4d5d3b1a6ddbb48ba34c..0a46582299c8cfdf3c1e4ff7e22bb1a80cc75cb4 100644
--- a/core/tests/Drupal/Tests/Core/Utility/UnroutedUrlAssemblerTest.php
+++ b/core/tests/Drupal/Tests/Core/Utility/UnroutedUrlAssemblerTest.php
@@ -97,8 +97,8 @@ public function providerTestAssembleWithExternalUrl() {
       ['https://example.com/test', ['https' => FALSE], 'http://example.com/test'],
       ['https://example.com/test?foo=1#bar', [], 'https://example.com/test?foo=1#bar'],
       'override-query' => ['https://example.com/test?foo=1#bar', ['query' => ['foo' => 2]], 'https://example.com/test?foo=2#bar'],
-      'override-query-merge' => ['https://example.com/test?foo=1#bar', ['query' => ['bar' => 2]], 'https://example.com/test?bar=2&foo=1#bar'],
-      'override-deep-query-merge' => ['https://example.com/test?foo=1#bar', ['query' => ['bar' => ['baz' => 'foo']]], 'https://example.com/test?bar%5Bbaz%5D=foo&foo=1#bar'],
+      'override-query-merge' => ['https://example.com/test?foo=1#bar', ['query' => ['bar' => 2]], 'https://example.com/test?foo=1&bar=2#bar'],
+      'override-deep-query-merge' => ['https://example.com/test?foo=1#bar', ['query' => ['bar' => ['baz' => 'foo']]], 'https://example.com/test?foo=1&bar%5Bbaz%5D=foo#bar'],
       'override-fragment' => ['https://example.com/test?foo=1#bar', ['fragment' => 'baz'], 'https://example.com/test?foo=1#baz'],
       ['//www.drupal.org', [], '//www.drupal.org'],
     ];