Brian MacMahon (disambiguation)

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