A.P.O. Akratitos Ano Liosia (Greek: Α.Π.Ο. Ακράτητος Άνω Λιοσίων) is a Greek football professional club from Ano Liosia, Athens, Greece. They currently play in the Alpha Division of the Football League championship, which is the third level of the Greek football pyramid. They maintain a quite strong academy of youngsters.
Akratitos spent their first years in relative obscurity, until they rose from the lower ranks to the top flight under the managership of Giannis Pathiakakis, who died on the pitch during a training session in 2002. The stadium was subsequently named after him.
Akratitos spent 3 consecutive seasons (2001-02 until 2003–04) in the Alpha Ethniki before being relegated in 2004 after losing a relegation match against Ergotelis which took place in Makedonikos Stadium, Thessaloniki. The following season Akratitos were re-promoted to Alpha Ethniki.
The 2005-06 season was meant to be their last in the Greek top-flight, as they finished last and were relegated again to the Beta Ethniki, but they decided to withdraw from the professional leagues completely and were automatically demoted to the Delta Ethniki. During that season they also achieved the lowest attendance ever in the Alpha Ethniki, with only 26 spectators watching their home game against Skoda Xanthi.
The team faced another relegation in 2009, when they finished 12th in Group 7 of the Delta Ethniki and got relegated to the local West Attica championships.