Gertrude Blanch (2 February 1897, in Kolno, Russian Empire (now Poland) – 1 January 1996) was an American mathematician who did pioneering work in numerical analysis and computation. She was a leader of the Mathematical Tables Project in New York from its beginning. She worked later as the assistant director and leader of the Numerical Analysis at UCLA computing division and was head of mathematical research for the Aerospace Research Laboratory at Wright-Patterson Air Force Base in Dayton, Ohio.