In a large bowl, beat the pudding mix and the milk for 2 minutes with a mixer.
Blend the sweetened condensed milk into the pudding mixture. Let mixture sit for 2 minutes.
Stir the vanilla extract into the pudding mixture.
Fold the whipped topping into the pudding mixture.
in a 9 X 13 pan, layer vanilla wafers evenly on the bottom.
Spread half of the pudding mixture onto the wafer layer.
Spread banana slices evenly over the pudding layer.
Repeat vanilla wafer layer and then cover with the remaining half of pudding mixture.
Cover and chill for about 2 hours in the refrigerator before serving.