Ladner is a surname. Notable people with the surname include:
Benjamin Ladner, academic philosopher and theologian
Bobby Ladner, American football coach
Don Ladner (1948/1949-2009), a New Zealand rugby league player
Jay Ladner (born 1965), American basketball coach
Joyce Ladner, United States civil rights activist, author, civil servant and sociologist
Kurt Ladner, a pen name of Nelson DeMille
Leon Johnson Ladner (1884–1978), Canadian lawyer and Conservative politician
Luca Ladner (born 1989), Swiss footballer
Marco Ladner (born 1998), Austrian freestyle skier
Matthew Ladner (born 1967)
Peter Ladner, Vancouver city councillor
Richard Ladner, of Ladner's theorem in computational complexity
Wendell Ladner, former American professional basketball player
William Henry Ladner, (1826–1907) English-born miner, farmer and political figure in British Columbia
