diff --git a/lib/compat/wordpress-6.8/post.php b/lib/compat/wordpress-6.8/post.php
new file mode 100644
index 0000000000000..5032476648899
--- /dev/null
+++ b/lib/compat/wordpress-6.8/post.php
@@ -0,0 +1,26 @@
+<?php
+
+/**
+ * Set the default editor mode for the page post type to `template-locked`.
+ *
+ * Note: This backports into `create_initial_post_types` in WordPress Core.
+ *
+ * @param array $args Array of post type arguments.
+ * @return array Updated array of post type arguments.
+ */
+function gutenberg_update_page_editor_support( $args ) {
+	if ( empty( $args['supports'] ) ) {
+		return $args;
+	}
+
+	$editor_support_key = array_search( 'editor', $args['supports'], true );
+	if ( false !== $editor_support_key ) {
+		unset( $args['supports'][ $editor_support_key ] );
+		$args['supports']['editor'] = array(
+			'default_mode' => 'template-locked',
+		);
+	}
+
+	return $args;
+}
+add_action( 'register_page_post_type_args', 'gutenberg_update_page_editor_support' );
diff --git a/lib/load.php b/lib/load.php
index b145d44376280..69ba59e371884 100644
--- a/lib/load.php
+++ b/lib/load.php
@@ -97,6 +97,7 @@ function gutenberg_is_experiment_enabled( $name ) {
 require __DIR__ . '/compat/wordpress-6.8/preload.php';
 require __DIR__ . '/compat/wordpress-6.8/blocks.php';
 require __DIR__ . '/compat/wordpress-6.8/functions.php';
+require __DIR__ . '/compat/wordpress-6.8/post.php';
 require __DIR__ . '/compat/wordpress-6.8/site-editor.php';
 require __DIR__ . '/compat/wordpress-6.8/class-gutenberg-rest-user-controller.php';