The Propylaia is the entrance to the Acropolis. It was abandoned unfinished in 432 because of the Peloponnesian War. It was built on a problematic slope, but with a grandiose plan. It is T-shaped in design, with six Doric columns at both east and west ends, and in pairs of three either side of central ramp. The wall is pierced by four doors (two on each side) at head of a flight of five steps that mark the transition between eastern and western porticoes (and moment of entry onto the Acropolis). In western side there are rectangular hallways with a wall on one side and columns on other (three Ionic columns).

The architect, Mnesikles, envisioned two large buildings to the right and left of portico, within the Acropolis. They were begun, but never completed. He also planned two smaller rooms on outside to west, but only one to north was completed, with three columns "in antis" and a window on either side of the door. The room was intended to be a Pinakotheke (picture gallery) and was adorned with movable paintings on wooden boards.