Callendar is a title of Scottish nobility and a surname. It may refer to:
Earl of Callendar Callendar House, Falkirk Guy Stewart Callendar (1898 – 1964), English steam engineer and inventor and son of Hugh Longbourne Callendar Callendar effect Hugh Longbourne Callendar (1863 – 1930), British physicist and father of Guy Stewart Callendar
See also
Calendar - (chronological system or book) Calender - (roller system) Callander - (Town in Scotland) Callender (disambiguation) Colander (kitchen utensil) Qalandar (disambiguation)