Kalajdžić () is a Serbo-Croatian surname, derived from the occupation kalajdžija (tinker). Notable people with the surname include:
Avdo Kalajdžić (born 1959), former Bosnian professional footballer Muhamed Bekir Kalajdžić (1892–1963), Bosnian writer, bookseller and publisher Radivoje Kalajdzic (born 1991), Bosnian-American professional boxer Sasa Kalajdzic (born 1997), Austrian professional footballer Željko Kalajdžić (born 1978), Serbian professional football coach and former player