Mary R. Calvert (20 June 1884 – June 1974) was an American astronomer.
In 1905, she started work at Yerkes Observatory, as assistant and computer for her uncle, Edward Emerson Barnard (1857–1923).
In 1923, when Barnard died, she became curator of the Yerkes photographic plate collection and a high-level assistant, until her retirement in 1946.
Barnard’s work 'A Photographic Atlas of Selected Regions of the Milky Way' was completed after his death in 1923 by Edwin B. Frost, director of the Yerkes Observatory, and Calvert, and published in 1927.
She died in Nashville in 1974.