Tic-tac-toe is a paper-and-pencil game for two players, X and O, who take turns marking the spaces in a 3×3 grid. The player who succeeds in placing three of their marks in a horizontal, vertical, or diagonal row wins the game. The following example game is won by the first player, X: Game of Tic-tac-toe, won by X. Play the classic Tic-Tac-Toe game (also called Noughts and Crosses) for free online with one or two players. Strategic Tic Tac Toe at Cool Math Games: Think you're a Tic Tac Toe pro? Is it too simple? Try this version, which is like a game of Tic Tac Toe inside another. Confused? You'll have to try it out!