Hajdú and Hajdu may refer to:
Hajdu, mercenary soldiers in 16th- and 17th-century Hungary Hajdú (county), a historical county in the Kingdom of Hungary Hajdú-Bihar, a modern county in eastern Hungary Hajdu–Cheney syndrome, an extremely rare genetic disorder of the connective tissue Hajdú, a surname: Andre Hajdu (1932–2016), Israeli composer born in Hungary David Hajdu (born 1955), American columnist Étienne Hajdú (1907–1996), Transylvania-born French sculptor Georg Hajdu (born 1960), German composer and music theorist Júlia Hajdú (1925–1987), Hungarian composer and pianist Lili Hajdú Gimesné (1891–1960), Hungarian psychiatrist and psychoanalyst Markéta Hajdu (born 1974), Czech hammer thrower Márton Hajdu, Hungarian politician Patty Hajdu (born 1966), Canadian politician