Ronald Bon de Sousa Pernes (/də ˈsuːzə/ də SOO-zə; born 1940) is a Swiss-born Canadian philosopher and academic.
He is an emeritus professor at the Department of Philosophy of the University of Toronto, which he joined in 1966.
De Sousa possesses both UK and Canadian citizenship.
His thesis Categories, Translation, and Linguistic Theory was supervised by Paul Benacerraf.
He was elected a fellow of the Royal Society of Canada in 2005.