Nicholas Theodore Varopoulos (Greek: Νικόλαος Βαρόπουλος, Nikolaos Varopoulos, also Nicolas Varopoulos; born 16 June 1940) is a Greek mathematician, who works on harmonic analysis and especially analysis on Lie groups. In 1968 Varopoulos became the first recipient of the Salem Prize. In 1990 he was an invited speaker at the International Congress of Mathematicians in Kyoto (Analysis and geometry on groups) and in 1970 in Nice (Groupes des fonctions continues en analyse harmoniques). His doctoral students include Thomas William Körner and Laurent Saloff-Coste.