Whack-O! was a British sitcom TV series starring Jimmy Edwards, written by Frank Muir and Denis Norden, and broadcast from 1956 to 1960 and 1971 to 1972.

The series ran on the BBC from 1956 to 1960 and from 1971 to 1972. Edwards took the part of Professor James Edwards, M.A., the drunken, gambling, devious, cane-swishing headmaster who tyrannised staff and children at Chiselbury public school. The Edwards character bore more than a passing resemblance to Sergeant Bilko as he tried to swindle the children out of their pocket money to finance his many schemes.