Unlike Late Roman/Early Byzantine amphorae, Middle and Late Byzantine amphorae have been little studied and their origins and contents are still largely unknown. Out of the four main types distinguished by Günsenin, two were investigated in the present research: types Günsenin II (10th-11th century AD) and Günsenin III (12th-13th century AD). Samples taken from various excavations and find spots in central Greece, located in Thebes, Chalcis, and the countryside of Euboea were investigated for their provenance by chemical analysis. Thanks to previously established reference groups, samples of amphorae Günsenin III, of part of amphorae Günsenin II and of transitional types could be attributed to Chalcis, whose harbor played a major role in the Aegean at the medieval period.