Tic-Tac-Toe is a pencil-and-paper game for two players, X and O, who take turns marking the spaces in a grid. The player who succeeds in placing three respective marks in a horizontal, vertical, or diagonal line wins. Put away your pencil and paper and play Tic Tac Toe on your Android phone for free. It is a great way to pass the time by playing Tic Tac Toe.