UNO Online by Mattel games.This online UNO of the popular card game UNO ensures that you can now play your favorite card game whenever you want! As you know, the goal is to get rid of your cards before your opponents do. When you have only one card left, don't forget to hit the UNO button! Uno is a registered trademark by Mattel. Don't forget to buy the physical game if you like this online version!