Maria Kaupas, S.S.C., (January 6, 1880 – April 17, 1940) was an American Catholic religious sister who founded the Sisters of Saint Casimir. She was born Casimira Kaupas in Ramygala, Russian Empire. At the age of 17, she emigrated to the United States, where she settled in Scranton, Pennsylvania, to work as a housekeeper for her brother, Anthony Kaupas, who was pastor of St. Joseph Parish there. While there, she had her first contact with religious sisters and was attracted by their way of life. She also became aware of her countrymen's struggle due to the language barrier, especially in their spiritual life.