The trittyes // (Ancient Greek: τριττύες trittúes), singular trittys // (τριττύς trittús), were population divisions in ancient Attica, established by the reforms of Cleisthenes in 508 BC. The name means "third". There were thirty trittyes and ten tribes in Attica. Each tribe was composed of three trittyes, one from the coast (paralia), one from the city (asty), and one from the inland area (mesogeia). Trittyes were composed of one or more demes; demes were the basic unit of division in Attica.
- Fine, John V.A. The Ancient Greeks: A critical history (Harvard University Press, 1983) ISBN 0-674-03314-0
- Traill, John S., The political organization of Attica: a study of the demes, trittyes, and phylai, and their representation in the Athenian Council, Princeton : American School of Classical Studies at Athens (ASCSA), 1975