Mary Olivia may refer to:
Mary Olivia Charteris, birth name of Lady Mary Charteris (born 1987), English fashion model, DJ, and musician; past member of English electronic rock band The Big Pink Mary Olivia Gowan (1888–1977), American nurse, Roman Catholic nun, and academic Mary Olivia Kennedy (1880–1943), Irish journalist Mary Olivia Nutting (1831–1910), American author and librarian