diff --git a/framework/db/mssql/QueryBuilder.php b/framework/db/mssql/QueryBuilder.php
index 993abe7d7e..493e40a403 100644
--- a/framework/db/mssql/QueryBuilder.php
+++ b/framework/db/mssql/QueryBuilder.php
@@ -334,7 +334,7 @@ class QueryBuilder extends \yii\db\QueryBuilder
             $columnSchemas = $tableSchema->columns;
             foreach ($columns as $name => $value) {
                 // @see https://github.com/yiisoft/yii2/issues/12599
-                if (isset($columnSchemas[$name]) && $columnSchemas[$name]->type === Schema::TYPE_BINARY && $columnSchemas[$name]->dbType === 'varbinary' && is_string($value)) {
+                if (isset($columnSchemas[$name]) && $columnSchemas[$name]->type === Schema::TYPE_BINARY && $columnSchemas[$name]->dbType === 'varbinary' && (is_string($value) || $value === null)) {
                     $exParams = [];
                     $phName = $this->bindParam($value, $exParams);
                     $columns[$name] = new Expression("CONVERT(VARBINARY, $phName)", $exParams);