Knock Castle is a ruined tower house in Aberdeenshire, north-east Scotland. It is typical of the traditional type of residence of a laird, a Scottish landed gentleman. Knock Castle is in Royal Deeside, about 1 mile (1.6 km) west of the town of Ballater, and about 6 miles (9.7 km) east of Balmoral. It sits on a knoll in a field on the south side of Craig of the Knock, a low hill at the entrance to Glen Muick. The castle is a category B listed building, and is in the care of Historic Environment Scotland.