Ronald Bon de Sousa Pernes ( ; 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 British and Canadian citizenship. Educated in Switzerland and England, he took his B.A. at New College, Oxford University, in 1962, and his Ph.D. at Princeton University in 1966. His thesis, Categories, Translation, and Linguistic Theory, was supervised by Paul Benacerraf.
He is best known for his work in the philosophy of emotions, and he has made contributions to the philosophy of mind and philosophy of biology. He was elected a fellow of the Royal Society of Canada in 2005.