Dayhoff is a surname. Notable people with the surname include:
Harry Dayhoff (1896–1963), American football player Margaret Oakley Dayhoff (1925–1983), American physical chemist and bioinformatician Ruth Dayhoff (born 1952), American physician and bioinformatician, daughter of Margaret Richard Paul Dayhoff (born 1959), American fraud examiner and auditor, son of Paul