Alister Williamson (17 June 1918 – 19 May 1999) was an Australian-born character actor, who appeared in many British films and television series of the 1960s and 1970s.

He also made appearances in many popular sitcoms of the period, such as Please Sir!, Dad's Army, The Galton and Simpson Playhouse, George and Mildred, The Likely Lads, Man About the House and That's My Boy.

In films he often appeared in the horror genre, either as policemen or landlords for companies such as Hammer Studios, Amicus and AIP throughout the 1960s and early 1970s.

In 1969 he appeared in Gordon Hessler's The Oblong Box, in which he would have his only leading role opposite stars Vincent Price and Christopher Lee.

In a part originally earmarked for Price, he played the disfigured Sir Edward Markham, acting underneath a red velvet hood until the film's climatic unmasking.