Mary Gertrude (1884–1965) was an Irish-born Australian nurse, Roman Catholic nun, and provincial superior.
Mary Gertrude may also refer to: Mary Gertrude Banahan (c. 1856–1932), New Zealand Roman Catholic nun and teacher Mary Gertrude Enig (1931–2014), American nutritionist and researcher Mary Gertrude Haseman (1889–1979), American mathematician Mary Gertrude Joyce (1884–1964), Irish-born New Zealand Roman Catholic nun and musician