Mary John is a feminine given name. Notable people with the name include:
Mary John Batten (1921–2015), Canadian lawyer, judge, and political figure Mary John Koothattukulam (1905–1998), Malayalam language poet Mary John Mananzan (born 1937), Filipino Roman Catholic nun, activist, educator, theologian, and author Mary John Sr. (1913–2004), Canadian Indigenous leader Mary John Thottam (1901–1985), Indian Catholic nun and poet