In a large bowl, whisk together mayonnaise, mustard, vinegar, sugar, salt, pepper and celery seeds in a bowl.
1/2 cup mayonnaise, 1/4 cup prepared yellow mustard, 1/4 cup apple cider vinegar, 1/4 cup granulated sugar, 2 tsps kosher salt, 2 tsps course ground black pepper, 1 tsp celery seed