Robert Berriedale Keith Dewar (June 21, 1945 – June 30, 2015) was an English-born American computer scientist and educator. He helped to develop software languages and compilers and was an outspoken advocate of freely licensed open source software. He was a founder, CEO and president of AdaCore software company. He was also an enthusiastic amateur performer and musician, especially with the Village Light Opera Group in New York City.