Sister Marion Beiter OSF (August 23, 1907 – October 11, 1982), born Dorothy Katharine Beiter, was an American mathematician and educator.
[1] Beiter was born in Buffalo to Kathryn (née Kiel) and Edward Frederick Beiter, where she attended Sacred Heart Academy.
[2] She entered the Sisters of St. Francis of Penance and Christian Charity in 1923, and professed her final vows in 1929.
She began her career in 1925 as a teacher in parochial and private schools, continuing in this capacity until 1952, when she was appointed chairwoman of the mathematics department of Rosary Hill College.
[4] Besides a sabbatical year at the State University of New York at Buffalo in 1971–1972, Beiter remained at Rosary Hill until her retirement in May 1977.