Dayman is a surname. Notable people with the surname include:
Edward Dayman (1807–1890), English clergyman and hymn writer
Greg Dayman (born 1947), former field hockey player from New Zealand
Ivan Dayman, Australian record producer and band manager of the 1960s and 1970s
Les Dayman (1901-?), Australian rules footballer
Leslie Dayman (born 1933), Australian actor