Play Game Tic-Tac-Toe : X vs O Tic-tac-toe (or Noughts and crosses, Xs and Os) is a pencil-and-paper game for two players, X and O, now you can play TicTacToe on your Android phone,who take turns marking the spaces in a 3×3 grid. The player who succeeds in placing three respective marks in a horizontal, vertical, or diagonal row wins the game.