Ατρόμητος Πειραιώς) is a Greek football club based in Piraeus, Greece.

They are currently competing in the Local Championship of Piraeus after having been relegated from the third tier of the Greek football league system, Gamma Ethniki.

Before World War II and during the German occupation the existence of the team played an important role for the development and advancement of amateur football.

In the national championship, Atromitos finished fourth among six teams.

From 1962 season to 1979 played in B Ethniki taking away several times good places in the final standings.