Geach is a surname. Notable people with the surname include:
Carveth Geach (1928–2005), Chief Scout of the Boy Scouts of South Africa David Geach (1923–2015), RAF bomb aimer Peter Geach (1916–2013), British philosopher and professor Portia Geach (1973–1959), Australian artist and feminist Trevor Geach (1928–1996), South African cricketer