George Costakis (Russian: Георгий Дионисович Костаки, Greek: Γεώργιος Κωστάκης, 5 July 1913 - 1990) was a collector of Russian art whose collection became the most representative body of Modern Russian avant-garde art anywhere. In the years surrounding the 1917 revolution, artists in Russia produced the first non-figurative art, which was to become the defining art of the 20th century. Costakis by chance discovered some constructivist paintings in a Moscow studio in 1946, and he went on to search for the revolutionary art which might otherwise have been lost to the world.