Thanassis Stephopoulos (Greek: Θανάσης Στεφόπουλος, 1 June 1928 – 29 December 2012) was one of Greece's most important 20th-century painters, teachers and philosophers of art. He was famous for his works, representing a genre of painting which he had introduced, the abstract landscape painting. He was one of the most important representatives of the so-called Modern Greek art.