Westheimer is a surname. Notable people with the surname include:
David Westheimer (1917–2005), American novelist Frank Henry Westheimer (1912–2007), American chemist Gerald Westheimer (born 1924), Australian vision scientist and neuroscientist Irvin Ferdinand Westheimer (1879–1980), American founder of the Big Brothers Big Sisters of America Julius Westheimer (1916–2005), American financial advisor Ruth Westheimer (1928–2024), German-American sex therapist, talk show host, and Holocaust survivor Joel Westheimer, American professor at the University of Ottawa, son of the above