Tic-Tac-Dough is an American television game show based on the paper-and-pencil game of tic-tac-toe. Contestants answer trivia questions to put up their respective symbol, X or O, on a gameboard. Three versions were produced: the initial 1956–59 run on NBC, a 1978–86 run on CBS and then in syndication, and a syndicated run in 1990.