diff --git a/packages/native-stack/src/types.tsx b/packages/native-stack/src/types.tsx
--- a/packages/native-stack/src/types.tsx
+++ b/packages/native-stack/src/types.tsx
@@ -1010,6 +1010,14 @@
    */
   hidesSharedBackground?: boolean | undefined;
   /**
+   * Supported bar axes and preferred placement, matching UIBarButtonItem.axisBehavior.
+   * Only supported by the new native stack on iOS 27.1 and later,
+   * when react-native-screens is built with the iOS 27.1 SDK or newer.
+   * Defaults to automatic; removing the option restores automatic.
+   * Ignored on other platforms and older iOS versions.
+   */
+  axisBehavior?: 'automatic' | 'horizontalOnly' | 'verticalPreferred' | undefined;
+  /**
    * Whether this item can share a background with other items.
    * Only available from iOS 26.0 and later.
    *
@@ -1315,6 +1323,14 @@
    * Read more: https://developer.apple.com/documentation/uikit/uibarbuttonitem/hidessharedbackground
    */
   hidesSharedBackground?: boolean | undefined;
+  /**
+   * Supported bar axes and preferred placement, matching UIBarButtonItem.axisBehavior.
+   * Only supported by the new native stack on iOS 27.1 and later,
+   * when react-native-screens is built with the iOS 27.1 SDK or newer.
+   * Defaults to automatic; removing the option restores automatic.
+   * Ignored on other platforms and older iOS versions.
+   */
+  axisBehavior?: 'automatic' | 'horizontalOnly' | 'verticalPreferred' | undefined;
 };
 
 /**
diff --git a/packages/native-stack/src/next/views/useHeaderConfig.ios.tsx b/packages/native-stack/src/next/views/useHeaderConfig.ios.tsx
--- a/packages/native-stack/src/next/views/useHeaderConfig.ios.tsx
+++ b/packages/native-stack/src/next/views/useHeaderConfig.ios.tsx
@@ -129,6 +129,7 @@
         type: 'item',
         title: item.label,
         icon: getIOSHeaderIcon(item.icon),
+        axisBehavior: item.axisBehavior,
         onPress: item.onPress,
       };
     }
@@ -141,6 +142,7 @@
         type: 'item',
         title: item.label,
         icon: getIOSHeaderIcon(item.icon),
+        axisBehavior: item.axisBehavior,
         menu: {
           ...getIOSHeaderMenu(item.menu, `${id}-menu`),
           title: item.menu.title,
@@ -161,6 +163,7 @@
       id: fallbackId,
       type: 'item',
       render: () => item.element,
+      axisBehavior: item.axisBehavior,
     };
   });
 }