Brian MacMahon (1923–2007) is a British-american epidemiologist.
Brian MacMahon may also refer to: Brian MacMahon of Macmahon Holdings Col. Brian MacMahon in Confederate Ireland Bryan MacMahon (judge) (born 1941), Irish judge Bryan MacMahon (writer) (1909–1998), Irish writer Brian MacMahon (runner) (active 2012), Irish runner
See also Brian McMahon (disambiguation)