Mix the instant pudding and milk with electric mixer until firm as directed.
Crumble the Oreos in a food processor or do as I do and crush them in the bag after I take out the plastic holder inside the bag.
In a large bowl, layer the Oreo crumbles, then the pudding, and lastly the Cool Whip. Continue to layer all ingredients until you have used up everything. Make sure the Cool whip is the last layer and add a few crumbles of the Oreos on top to decorate.
You can also add another layer (flavor) by mixing a box of instant vanilla or cream cheese pudding and adding into the layering.