Richard Paul Winsley Thomas FRS is a British mathematician working in several areas of geometry. He is a professor at Imperial College London. He studies moduli problems in algebraic geometry, and ‘mirror symmetry’—a phenomenon in pure mathematics predicted by string theory in theoretical physics. In 2004, Thomas was awarded the London Mathematical Society's Whitehead Prize and the Philip Leverhulme Prize, in 2010 the Royal Society Wolfson Research Merit Award. For 2025 he was awarded the Oswald Veblen Prize in Geometry, shared with Soheyla Feyzbakhsh.