diff --git a/src/codegen/Common.ts b/src/codegen/Common.ts
index dfa0c51be6..acc5b0ac88 100644
--- a/src/codegen/Common.ts
+++ b/src/codegen/Common.ts
@@ -800,6 +800,12 @@ const common = {
           .optional({ default: false })
           .setDescription('Whether this group should mark pages as completed when the user finishes'),
       ),
+      new CG.prop(
+        'expandedByDefault',
+        new CG.bool()
+          .optional({ default: false })
+          .setDescription('Whether the sidebar group should be expanded by default'),
+      ),
     ),
   IPagesSettingsWithGroups: () =>
     new CG.obj(
diff --git a/src/features/navigation/components/PageGroup.tsx b/src/features/navigation/components/PageGroup.tsx
index dee1d49edc..2cc861aa1a 100644
--- a/src/features/navigation/components/PageGroup.tsx
+++ b/src/features/navigation/components/PageGroup.tsx
@@ -132,8 +132,11 @@ function PageGroupMultiple({
   const buttonId = `navigation-button-${group.id}`;
   const listId = `navigation-page-list-${group.id}`;
 
-  const [isOpen, setIsOpen] = useState(containsCurrentPage);
-  useLayoutEffect(() => setIsOpen(containsCurrentPage), [containsCurrentPage]);
+  const [isOpen, setIsOpen] = useState(containsCurrentPage || !!group.expandedByDefault);
+  useLayoutEffect(
+    () => setIsOpen(containsCurrentPage || !!group.expandedByDefault),
+    [containsCurrentPage, group.expandedByDefault],
+  );
 
   const pageGroupHasErrors = validations !== ContextNotProvided && validations.hasErrors.group;
   const pageGroupIsComplete = validations !== ContextNotProvided && validations.isCompleted.group;