Gruppo Sigma (Greek: Ομάδα Σίγμα) was a short-lived group of young Greek artists founded in 1958 in Italy. It is a prime example of the Greek artistic avant-garde that flourished outside Greece during the postwar period and the first attempt by Greek artists who had been educated abroad to present joint exhibitions.^[1]

Gruppo Sigma was founded in 1958 in Rome by the Greek painters Vlassis Caniaris, Yannis Gaïtis, Nikos Kessanlis, Mimis Kontos and Costas Tsoclis.^[2][3][4][5] The members of the group were young and avant-garde artists living abroad, all in Rome with the exception of Gaïtis, who lived in Paris, and were knowledgeable of the contemporary art movements of their time.^[3]

The group aimed to highlight the Greek presence and identity in the international art world and to foster artistic and exhibition-related cooperation among its members. As a group, it was short-lived and held only two exhibitions, in 1959 in Naples and Bologna;^[6][7] nevertheless, it managed to leave its mark, earning positive reviews in Greece and Italy.^[2][3] Moreover Gruppo Sigma was the first attempt by Greek artists who had studied abroad to organize joint exhibitions.^[1]

• Bolis, Yannis; Misirloglou, Thouli. Untitled II Greek Postwar Abstraction: the heroic years (PDF). ΜΟΜus.
• Lambraki–Plaka, Marina, ed. (1999). Εθνική Πινακοθήκη 100 χρόνια: Τέσσερις αιώνες Ελληνικής Ζωγραφικής (in Greek). Athens: National Gallery of Greece.