diff --git a/core/modules/layout_builder/src/Controller/ChooseBlockController.php b/core/modules/layout_builder/src/Controller/ChooseBlockController.php
index a20a351d56..f38b16833a 100644
--- a/core/modules/layout_builder/src/Controller/ChooseBlockController.php
+++ b/core/modules/layout_builder/src/Controller/ChooseBlockController.php
@@ -159,7 +159,7 @@ public function build(SectionStorageInterface $section_storage, $delta, $region)
     foreach ($grouped_definitions as $category => $blocks) {
       $block_categories[$category]['#type'] = 'details';
       $block_categories[$category]['#attributes']['class'][] = 'js-layout-builder-category';
-      $block_categories[$category]['#open'] = TRUE;
+      $block_categories[$category]['#open'] = FALSE;
       $block_categories[$category]['#title'] = $category;
       $block_categories[$category]['links'] = $this->getBlockLinks($section_storage, $delta, $region, $blocks);
     }