Julien Ariel De Sart (born 23 December 1994) is a Belgian professional footballer who plays as a defensive midfielder for Qatari club Al-Rayyan.

De Sart went on to sign his first professional contract with the club's senior team in 2013, making his debut in that same year.

[citation needed] On 22 August 2013, De Sart made his debut in the UEFA Europa League against Belarusian FC Minsk in a 2–0 away win.

[citation needed] On 1 February 2016, it was confirmed that De Sart had joined English club Middlesbrough of the Championship side on a three-and-a-half-year contract for an undisclosed fee.

[5] On 27 June 2017, De Sart was sent on loan to Belgian Pro League team Zulte Waregem for the 2017–18 season, thus making a return to Belgium after leaving Standard Liège in January 2016.