Mary Leopoldina Burns (August 28, 1856 – June 3, 1942), was an American religious sister who was a member of the Sisters of St Francis of Syracuse, New York, and a close companion and biographer of Marianne Cope during the 1883 Hansen's Disease epidemic on the island of Molokaʻi, Hawaii.

[2] Together with Marianne Cope and five other sisters, they departed from Syracuse to travel to Honolulu to answer the request of King Kalākaua of Hawaii to care for leprosy sufferers arriving on November 8, 1883.

With Mother Marianne as supervisor, the sisters' task was to manage Kakaʻako Branch Hospital on Oʻahu, which served as a receiving station for Hansen's disease patients gathered from all over the islands.

In 1889, together with Mother Marianne and Sister Vincentia McCormick, they opened and ran a girls' school in Hawaii, which they named in Henry Perrine Baldwin's honor, a prominent local businessman who supported their missions.

After serving for nearly 40 years on Molokai, Sister Leopoldina retired in 1928 to the St. Francis Convent in Manoa Valley where she lived until her death.