The architecture followed the standards of the classical period. The main facade, facing the Agora, consisted of five pillars between ante. The main hall was a plain square room with wooden seats along the three walls. Four massive ionic colunms, also arranged in a square, supported the roof.
The Bouleuterion at Assos, along with those at Miletus, Athens, and Heracleia belongs to an innovative group of buildings with wide inner space covered by roofs resting on a reduced number of columns. The foundation, the northern column of the facade, the bases of the inner columns and part of the superstructure are still preserved on the site today.