Theiler is a surname. Notable people with the surname include:
Arnold Theiler (1867–1936), South African scientist and veterinarian Gertrud Theiler (1897–1986), South African parasitologist Jorge Theiler (born 1964), Argentine football player and manager Luciano Theiler (born 1981), Argentine football player and manager Max Theiler (1899–1972), South African-American virologist and physician Rolf Theiler (born 1957), Swiss businessman
See also Theiler (crater), a lunar impact crater