Mary Kenneth Keller, B.V.M. (December 17, 1913 – January 10, 1985) was an American Catholic religious sister, educator and pioneer in computer science. She was the first person to earn a Ph.D. in computer science in the United States. Keller and Irving C. Tang were the first two recipients of computer science doctorates (Keller's Ph.D. and Tang's D.Sc. were awarded on the same day). She is part of the team that developed the BASIC programming language.