Clarence "Skip" Ellis was an American computer scientist, and Emeritus Professor of Computer Science and Cognitive Science at the University of Colorado at Boulder. While at the CU-Boulder, he was the director of the Collaboration Technology Research Group and a member of the Institute of Cognitive Science. Ellis was the first African-American to earn a Ph.D. in Computer Science (1969), and the first African-American to be elected a Fellow of the ACM (1997).