diff -u b/core/modules/views/templates/views-view-unformatted.html.twig b/core/modules/views/templates/views-view-unformatted.html.twig
--- b/core/modules/views/templates/views-view-unformatted.html.twig
+++ b/core/modules/views/templates/views-view-unformatted.html.twig
@@ -22,7 +22,6 @@
   {%
     set row_classes = [
       default_row_class ? 'views-row',
-      view.style_plugin.getRowClass(row.id),
     ]
   %}
   <div{{ row.attributes.addClass(row_classes) }}>
diff -u b/core/modules/views/views.theme.inc b/core/modules/views/views.theme.inc
--- b/core/modules/views/views.theme.inc
+++ b/core/modules/views/views.theme.inc
@@ -772,6 +772,9 @@
     $variables['rows'][$id]['content'] = $row;
     $variables['rows'][$id]['attributes'] = array();
     $variables['rows'][$id]['attributes'] = new Attribute($variables['rows'][$id]['attributes']);
+    if ($row_class = $view->style_plugin->getRowClass($id)) {
+      $variables['rows'][$id]['attributes']->addClass($row_class);
+    }
   }
 }