The Sisters of Saint Casimir are a Roman Catholic religious community of women founded in 1907 in Scranton, Pennsylvania by Mother Maria Kaupas. Mother Maria, a native of Lithuania, was found to have lived a life of heroic virtue by the Congregation of the Causes of Saints under Pope Benedict XVI in Rome on Thursday, July 1, 2010, according to an article posted on the website of Catholic News Service. The congregation's early work focused on Lithuanian immigrants in the United States.
The Sisterhood operates in Illinois, Pennsylvania, Washington, D.C., New Mexico and Argentina.
Some institutions sponsored by the Sisterhood are Villa Joseph Marie High School in Holland, Pennsylvania, and Holy Cross Hospital and Maria High School, both in Chicago, Illinois.