[[caption-width-right:256:Can't get 3 in a row. Can get 43 ''tie games'' in a row.\\
[-(Super NES version)-] ]]
Tic-tac-toe, also called tick tack toe, or noughts and crosses/Xs and Os as it is known in the United Kingdom, Australia and New Zealand, is a pencil-and-paper game of unknown origin. Two players, X and O, take turns marking the spaces in a 33 grid. The X player usually goes first. The player who succeeds in placing three respective marks in a horizontal, vertical, or diagonal row wins the game. If the board fills up before anyone accomplishes this (which is very likely to happen between players with any experience), the game is a draw.

The first video game, ''VideoGame/{{OXO}}'', is pretty much this in video game form. It was the basis for ''Series/TicTacDough'' and ''Series/TheHollywoodSquares'', as well as the Secret "X" game on ''Series/ThePriceIsRight''.
!!! Video game adaptations:
* ''VideoGame/{{OXO}}'' (1952) for the EDSAC.
* Tim Soft's ''[[http://www.zophar.net/pdroms/snes.html Tic-Tac-Toe]]'' (1994) for the SuperNES.
* Stephen Ostermiller's ''[[http://ostermiller.org/calc/tictactoe.html Tic-Tac-Toe]]'', one of many online versions. Includes a good [[http://ostermiller.org/calc/tictactoe.html strategy guide]].
* Neave Interactive's ''[[http://neave.com/tic-tac-toe/ Tic-Tac-Toe]]'', online Flash with sound effects.
!!! "Tic Tac Tropes":
* CasualVideoGame
* DifficultyLevels: Some computer players never lose. To give the human a chance, some video games have difficulty levels.
** Ostermiller's Tic-Tac-Toe has four difficulty levels: Novice makes random moves, Intermediate blocks two-in-a-row, Experienced makes the best first moves, and Expert plays perfectly.
** Tim Soft's Tic-Tac-Toe has Easy, Normal and Hard. If you find the flaw, you can still win about 1 in 4 games against Hard.
* HouseRules: Once the 3x3 grid gets too easy, players may trade up to a larger grid size. There's also a "3D" variant, played simultaneously on three separate grids (to simulate a cube), where getting three in a row in any direction (even across different grids) counts as a win.
** X typically goes first, but that's up to preference really.
* MatchThreeGame: Well, you need to get three X's or O's in a row, column or diagonal to win...
* PlayerVersusPlayer
* SeparatedByACommonLanguage: This game known as Tic-Tac-Toe in North America is known as Noughts and Crosses in the United Kingdom, Australia, and New Zealand.
* StrategyGame: One needs some strategy to avoid defeat in this game, as players are technically attacking ''and'' defending at the same time.
* UnwinnableByDesign: If two skilled players play the game, they will inevitably force themselves into a draw. Many computer players, starting with ''OXO'' from 1952, can play a perfect game with no mistakes, so it is impossible to win against them.
* VideoGame: UrExample. OXO, a 1952 version made for the computer, is believed to be the first computer/video game to use a digital graphics display.
!!! Appearances in media:
* ''Series/TicTacDough'': Game show. Answer questions, place X's and O's, win money.
* ''Series/TheHollywoodSquares'': Game show with nine celebrities sitting in a giant grid.
* ''Film/WarGames'': One of the computer games on WOPR is "Tic-Tac-Toe". This game is as unwinnable as "Global Thermonuclear War".
** SMBC theater did a parody of this scene where the computer concludes that the lesson is to go first and control your opponent's options. Ironically, its justification uses terrible tic-tac-toe strategy.
* ''Webcomic/{{xkcd}}'' provides the [[http://xkcd.com/832/ Complete Map of Optimal Tic-Tac-Toe Moves]]. You will never lose a game again! Its AltText is a ShoutOut to ''[=WarGames=]''.
--> ''"The only winning move is to play, perfectly, waiting for your opponent to make a mistake."''