Sir Simon Philip Baron-Cohen (born 15 August 1958) is a British clinical psychologist and professor of developmental psychopathology at the University of Cambridge. He is the director of the university's Autism Research Centre and a Fellow of Trinity College. In 1985, Baron-Cohen formulated the mind-blindness theory of autism, the evidence for which he collated and published in 1995. In 1997, he formulated the fetal sex steroid theory of autism, the key test of which was published in 2015.

He has also made major contributions to the fields of typical cognitive sex differences, autism prevalence and screening, autism genetics, autism neuroimaging, autism and technical ability, and synaesthesia. Baron-Cohen was knighted in the 2021 New Year Honours for services to autistic people.