If using pudding mix, make the pudding according to package directions.
Layer graham crackers in the bottom of a 9x11-inch (2-quart) baking dish. Break some up to fill in edges as needed.
Cover with ½ of the vanilla pudding, spreading to cover.
Top with another layer of graham crackers.
Cover with ½ of the chocolate pudding, spreading to cover.
Repeat the layers to finish, ending with chocolate pudding.
Top with crushed graham crackers.
Cover and refrigerate for at least 2 hours and up to overnight to soften the graham crackers. Serve cold.
