diff --git a/src/wp-includes/wp-db.php b/src/wp-includes/wp-db.php
index 5cc2be114f..c300e240f2 100644
--- a/src/wp-includes/wp-db.php
+++ b/src/wp-includes/wp-db.php
@@ -1243,7 +1243,7 @@ class wpdb {
 		}
 
 		foreach ( $args as $arg ) {
-			if ( ! is_scalar( $arg ) ) {
+			if ( ! is_scalar( $arg ) && ! is_null( $arg ) ) {
 				_doing_it_wrong( 'wpdb::prepare', sprintf( __( 'Unsupported value type (%s).' ), gettype( $arg ) ), '4.8.2' );
 			}
 		}