Line the bottom of a 9×13-inch pan with graham crackers.
In a large bowl, combine pudding mix and milk; stir well. Mix whipped topping into pudding mixture. Spread half of mixture over graham cracker layer. Top with another layer of graham crackers and the remaining pudding.
Top all with a final layer of graham crackers and frost with chocolate frosting. Refrigerate at least two hours before serving to allow the graham crackers to soften.