ΑΣΟ Τσλεφ U21

ASO Chlef was founded on June 13, 1947, as Association Sportive d'Orléansville, Orléansville being the colonial name of Chlef at the time. The club was founded by the indigenous Algerian Muslim community of the city who wanted a club to rival the already existing European club in the city, Groupement Sportif Orléansville. In its first season of existence, the club finished second in the third division. In the following two seasons, it won promotion to the first division. After Algeria gained its independence in 1962, the name of the city was changed from Orléansville to El Asnam and the club changed its name to Asnam Sportive Olympique, keeping its original ASO initials.

On June 21, 2005, ASO Chlef won its first domestic title after beating USM Sétif 1–0 in the final of the 2005 Algerian Cup with a goal from Mohamed Messaoud in extra-time. By winning the Cup, they also qualified for continental competition for the first time, earning a spot in the 2006 CAF Confederation Cup. However, their run in African competition came to a quick end. After walking over ASC Entente of Mauritania in the preliminary round, they lost to AS Douanes of Senegal 1–0 on aggregate in the first round.

In the 2007–08 season, ASO Chlef achieved its best league finish to date by finishing second in the Algerian Championnat National, 10 points behind champions JS Kabylie.

On June 21, 2011, led by head coach Meziane Ighil, ASO Chlef won its first Algerian Ligue Professionnelle 1 title after second-placed CR Belouizdad lost to USM El Harrach.

On May 12, 2012, ASO Chlef beat Sudanese club Al-Hilal 4–2 in a penalty shoot-out in the second round of the 2012 CAF Champions League after the two legs ended up tied 2–2 to qualify to the group stage for the first time in the club's history.