diff --git a/src/wp-includes/query.php b/src/wp-includes/query.php
index 4b5aa1730c..2dcc95c949 100644
--- a/src/wp-includes/query.php
+++ b/src/wp-includes/query.php
@@ -2448,6 +2448,9 @@ class WP_Query {
 		} elseif ( $q['post__in'] ) {
 			$post__in = implode(',', array_map( 'absint', $q['post__in'] ));
 			$where .= " AND {$wpdb->posts}.ID IN ($post__in)";
+		} elseif ( isset( $this->query['post__in'] ) ) {
+			$post__in = 0;
+			$where .= " AND 1=0 ";
 		} elseif ( $q['post__not_in'] ) {
 			$post__not_in = implode(',',  array_map( 'absint', $q['post__not_in'] ));
 			$where .= " AND {$wpdb->posts}.ID NOT IN ($post__not_in)";
@@ -2458,6 +2461,9 @@ class WP_Query {
 		} elseif ( $q['post_parent__in'] ) {
 			$post_parent__in = implode( ',', array_map( 'absint', $q['post_parent__in'] ) );
 			$where .= " AND {$wpdb->posts}.post_parent IN ($post_parent__in)";
+		} elseif ( isset( $this->query['post_parent__in'] ) ) {
+			$post_parent__in = 0;
+			$where .= " AND 1=0 ";
 		} elseif ( $q['post_parent__not_in'] ) {
 			$post_parent__not_in = implode( ',',  array_map( 'absint', $q['post_parent__not_in'] ) );
 			$where .= " AND {$wpdb->posts}.post_parent NOT IN ($post_parent__not_in)";
diff --git a/tests/phpunit/tests/query/results.php b/tests/phpunit/tests/query/results.php
index 20c45ba446..9c4ce065f9 100644
--- a/tests/phpunit/tests/query/results.php
+++ b/tests/phpunit/tests/query/results.php
@@ -402,6 +402,15 @@ class Tests_Query_Results extends WP_UnitTestCase {
 
 	}
 
+	function test_empty_post__in() {
+		$posts1 = $this->q->query( array() );
+		$this->assertNotEmpty( $posts1 );
+		$posts2 = $this->q->query( array( 'post__in' => array() ) );
+		$this->assertEmpty( $posts2 );
+		$posts3 = $this->q->query( array( 'post_parent__in' => array() ) );
+		$this->assertEmpty( $posts3 );
+	}
+
 	function test_exlude_from_search_empty() {
 		global $wp_post_types;
 		foreach ( array_keys( $wp_post_types ) as $slug )