Louis "Lou" Gerstman (April 22, 1930 - March 17, 1992) was an American neuropsychologist best known for his work in speech synthesis. He was a co-inventor, along with John Kelly, of the computer portrayed as HAL 9000 in the film 2001: A Space Odyssey. He also worked with Irv Teibel on Teibel's psychoacoustic environments recording series at Bell Labs, where Gerstman was working at the time.