Coser is a surname. Notable people with the surname include:
Achille Coser (born 1982), Italian footballer George Lucas Coser (born 1984), Brazilian footballer Lewis A. Coser (1913–2003), American sociologist Rose Laub Coser (1916–1994), German-American sociologist, educator, and social justice activist
See also Boards of Cooperative Educational Services, a program in New York State that provides cooperative services (CoSer) "Coser" as shortened spelling of "cosplayer"