diff --git a/packages/next-drupal/src/menu-tree.ts b/packages/next-drupal/src/menu-tree.ts
index b315d2797..f05ec9c7e 100644
--- a/packages/next-drupal/src/menu-tree.ts
+++ b/packages/next-drupal/src/menu-tree.ts
@@ -41,7 +41,7 @@ export class DrupalMenuTree<
 
       this.push({
         ...menuItem,
-        items: subtree.length ? subtree : undefined,
+        items: subtree.length ? subtree : null,
       })
     }
   }
diff --git a/packages/next-drupal/tests/DrupalMenuTree/drupal-menu-tree.test.ts b/packages/next-drupal/tests/DrupalMenuTree/drupal-menu-tree.test.ts
index aa8c3f3f5..ec0c6e329 100644
--- a/packages/next-drupal/tests/DrupalMenuTree/drupal-menu-tree.test.ts
+++ b/packages/next-drupal/tests/DrupalMenuTree/drupal-menu-tree.test.ts
@@ -67,7 +67,7 @@ DrupalMenuTree [
         "items": DrupalMenuTree [
           {
             "id": "7",
-            "items": undefined,
+            "items": null,
             "parent": "4",
           },
         ],
@@ -75,12 +75,12 @@ DrupalMenuTree [
       },
       {
         "id": "5",
-        "items": undefined,
+        "items": null,
         "parent": "1",
       },
       {
         "id": "6",
-        "items": undefined,
+        "items": null,
         "parent": "1",
       },
     ],
@@ -88,12 +88,12 @@ DrupalMenuTree [
   },
   {
     "id": "2",
-    "items": undefined,
+    "items": null,
     "parent": "",
   },
   {
     "id": "3",
-    "items": undefined,
+    "items": null,
     "parent": "",
   },
 ]
diff --git a/packages/next-drupal/tests/NextDrupal/__snapshots__/resource-methods.test.ts.snap b/packages/next-drupal/tests/NextDrupal/__snapshots__/resource-methods.test.ts.snap
index e376d202b..3b9c03168 100644
--- a/packages/next-drupal/tests/NextDrupal/__snapshots__/resource-methods.test.ts.snap
+++ b/packages/next-drupal/tests/NextDrupal/__snapshots__/resource-methods.test.ts.snap
@@ -493,7 +493,7 @@ exports[`getMenu() fetches menu items for a menu 1`] = `
       "enabled": true,
       "expanded": false,
       "id": "standard.front_page",
-      "items": undefined,
+      "items": null,
       "menu_name": "main",
       "meta": [],
       "options": [],
@@ -513,7 +513,7 @@ exports[`getMenu() fetches menu items for a menu 1`] = `
       "enabled": true,
       "expanded": false,
       "id": "views_view:views.featured_articles.page_1",
-      "items": undefined,
+      "items": null,
       "menu_name": "main",
       "meta": {
         "display_id": "page_1",
@@ -536,7 +536,7 @@ exports[`getMenu() fetches menu items for a menu 1`] = `
       "enabled": true,
       "expanded": false,
       "id": "views_view:views.recipes.page_1",
-      "items": undefined,
+      "items": null,
       "menu_name": "main",
       "meta": {
         "display_id": "page_1",
@@ -631,7 +631,7 @@ exports[`getMenu() fetches menu items for a menu with locale 1`] = `
       "enabled": true,
       "expanded": false,
       "id": "standard.front_page",
-      "items": undefined,
+      "items": null,
       "menu_name": "main",
       "meta": [],
       "options": [],
@@ -651,7 +651,7 @@ exports[`getMenu() fetches menu items for a menu with locale 1`] = `
       "enabled": true,
       "expanded": false,
       "id": "views_view:views.featured_articles.page_1",
-      "items": undefined,
+      "items": null,
       "menu_name": "main",
       "meta": {
         "display_id": "page_1",
@@ -674,7 +674,7 @@ exports[`getMenu() fetches menu items for a menu with locale 1`] = `
       "enabled": true,
       "expanded": false,
       "id": "views_view:views.recipes.page_1",
-      "items": undefined,
+      "items": null,
       "menu_name": "main",
       "meta": {
         "display_id": "page_1",