diff --git a/core/lib/Drupal/Core/Render/Renderer.php b/core/lib/Drupal/Core/Render/Renderer.php
index 2ff7c8b..3277b38 100644
--- a/core/lib/Drupal/Core/Render/Renderer.php
+++ b/core/lib/Drupal/Core/Render/Renderer.php
@@ -211,7 +211,13 @@ protected function doRender(&$elements, $is_root_call = FALSE) {
 
     // Render only the children if the #render_children property is set.
     if (isset($elements['#render_children'])) {
-      $children = Element::children($elements);
+      // A non-empty #children property takes precedence.
+      if (!empty($elements['#children'])) {
+        $children = ['#children'];
+      }
+      else {
+        $children = Element::children($elements);
+      }
 
       if (empty($children)) {
         return '';