diff --git a/core/modules/rest/src/Plugin/views/style/Serializer.php b/core/modules/rest/src/Plugin/views/style/Serializer.php
index 67a8364..f83d57f 100644
--- a/core/modules/rest/src/Plugin/views/style/Serializer.php
+++ b/core/modules/rest/src/Plugin/views/style/Serializer.php
@@ -122,9 +122,11 @@ public function render() {
     // which will transform it to arrays/scalars. If the Data field row plugin
     // is used, $rows will not contain objects and will pass directly to the
     // Encoder.
-    foreach ($this->view->result as $row) {
+    foreach ($this->view->result as $row_index => $row) {
+      $this->view->row_index = $row_index;
       $rows[] = $this->view->rowPlugin->render($row);
     }
+    unset($this->view->row_index);
 
     // Get the content type configured in the display or fallback to the
     // default.
diff --git a/core/modules/rest/src/Tests/Views/StyleSerializerTest.php b/core/modules/rest/src/Tests/Views/StyleSerializerTest.php
index a0f482a..4c4a51b 100644
--- a/core/modules/rest/src/Tests/Views/StyleSerializerTest.php
+++ b/core/modules/rest/src/Tests/Views/StyleSerializerTest.php
@@ -9,7 +9,10 @@
 
 use Drupal\Component\Utility\SafeMarkup;
 use Drupal\Core\Cache\Cache;
+use Drupal\Core\Field\FieldStorageDefinitionInterface;
 use Drupal\entity_test\Entity\EntityTest;
+use Drupal\field\Entity\FieldConfig;
+use Drupal\field\Entity\FieldStorageConfig;
 use Drupal\system\Tests\Cache\AssertPageCacheContextsAndTagsTrait;
 use Drupal\views\Entity\View;
 use Drupal\views\Plugin\views\display\DisplayPluginBase;
@@ -544,4 +547,76 @@ public function testFieldapiField() {
     $this->assertEqual($result[1]['nid'], $node->id());
     $this->assertTrue(strpos($this->getRawContent(), "<script") === FALSE, "No script tag is present in the raw page contents.");
   }
+
+  /**
+   * Tests the "Grouped rows" functionality.
+   */
+  public function testGroupRows() {
+    /** @var \Drupal\Core\Render\RendererInterface $renderer */
+    $renderer = $this->container->get('renderer');
+
+    $this->drupalCreateContentType(['type' => 'page']);
+
+    // Create a text field with cardinality set to unlimited.
+    $field_name = 'field_group_rows';
+    $field_storage = FieldStorageConfig::create([
+      'field_name' => $field_name,
+      'entity_type' => 'node',
+      'type' => 'string',
+      'cardinality' => FieldStorageDefinitionInterface::CARDINALITY_UNLIMITED,
+    ]);
+    $field_storage->save();
+
+    // Create an instance of the text field on the content type.
+    $field = FieldConfig::create([
+      'field_storage' => $field_storage,
+      'bundle' => 'page',
+    ]);
+    $field->save();
+
+    $grouped_field_values = ['a', 'b', 'c'];
+    $edit = [
+      'title' => $this->randomMachineName(),
+      $field_name => $grouped_field_values,
+    ];
+    $this->drupalCreateNode($edit);
+
+    $view = Views::getView('test_serializer_node_display_field');
+    $view->setDisplay('rest_export_1');
+    // Override the view's fields to include the field_group_rows field, set the
+    // group_rows setting to true.
+    $fields = [
+      $field_name => [
+        'id' => $field_name,
+        'table' => 'node__' . $field_name,
+        'field' => $field_name,
+        'type' => 'string',
+        'group_rows' => TRUE,
+      ],
+    ];
+    $view->displayHandlers->get('default')->overrideOption('fields', $fields);
+    $build = $view->preview();
+
+    // Get the serializer service.
+    $serializer = $this->container->get('serializer');
+
+    // Check if the field_group_rows field is grouped.
+    $expected = [];
+    $expected[] = [$field_name => implode(', ', $grouped_field_values)];
+    $this->assertEqual($serializer->serialize($expected, 'json'), (string) $renderer->renderRoot($build));
+
+    // Set the group rows setting to false.
+    $view = Views::getView('test_serializer_node_display_field');
+    $view->setDisplay('rest_export_1');
+    $fields[$field_name]['group_rows'] = FALSE;
+    $view->displayHandlers->get('default')->overrideOption('fields', $fields);
+    $build = $view->preview();
+
+    // Check if the field_group_rows field is ungrouped and displayed per row.
+    $expected = [];
+    foreach ($grouped_field_values as $grouped_field_value) {
+      $expected[] = [$field_name => $grouped_field_value];
+    }
+    $this->assertEqual($serializer->serialize($expected, 'json'), (string) $renderer->renderRoot($build));
+  }
 }