diff --git a/php/export/class-wp-export-query.php b/php/export/class-wp-export-query.php
index e228fbfcd4..6258d21691 100644
--- a/php/export/class-wp-export-query.php
+++ b/php/export/class-wp-export-query.php
@@ -356,7 +356,7 @@ private static function get_meta_for_post( $post ) {
 	private function get_comments_for_post( $post ) {
 		global $wpdb;
 
-		if ( $this->filters['skip_comments'] ) {
+		if ( isset( $this->filters['skip_comments'] ) ) {
 			return array();
 		}