Lehmer is a surname. Notable people with the surname include:
Derrick Norman Lehmer (1867–1938), number theorist who produced tables of prime factors and mechanical devices like Lehmer sievesDerrick Henry Lehmer (1905–1991), number theorist known for Lucas–Lehmer test, son of D. N. Lehmer and husband of Emma LehmerEmma Lehmer (1906–2007), Russian methematician, known for her work on reciprocity laws, wife of D. H. LehmerKat Lehmer, American film director, writer, actor and artist