Yllan Okou (born 23 December 2002) is a French professional footballer who plays as a centre-back for Belgian Pro League club RAAL La Louvière.
Born in Poitiers, Okou is the son of the Ivorian former rugby union player Alfred Okou. He moved to Buxerolles as a 7-year-old, whilst starting to play football with the Poitiers. There he was a close friend of Nicolas Tié, who would also end up pursuing a professional career in football at Chelsea and Vitória de Guimarães.
While playing his youth club football at Poitiers, Okou also joined the federal ' of Châteauroux in 2015. After this spell in the FFF institution, he entered the Monaco academy in 2017.
Okou made his professional debut for Monaco on 2 January 2022, starting and playing every minute of a Coupe de France 3âÂÂ1 away win against Quevilly-Rouen as a centre-back.
On 23 October 2023, Okou joined Ligue 2 club Bastia, signing a two-year contract with an option for a further year.
On 6 August 2025, Okou signed a three-season contract with RAAL La Louvière in Belgium.