2023–24 Royale Union Saint-Gilloise season

The 2023–24 season was Royale Union Saint-Gilloise's 126th season in existence and third consecutive in the Belgian Pro League. They also competed in the Belgian Cup, UEFA Europa League and the Europa Conference League. They reached the final of and won the Belgian Cup for the first time since 1914.

Out

 * Notes
 * 1.Exercised buy option.

Matches
The league fixtures were unveiled on 22 June 2023.

Champions' Play-offs
Union Saint-Gilloise finished first in the regular season and will start the Champions' play-offs on 35 points, their nearest rivals Anderlecht start three points behind them.

Play-off round
The draw for the play-off round was held on 7 August 2023.

Group stage
The draw for the group stage was held on 1 September 2023.

Knockout round play-off
The draw for the knockout round play-offs was held 18 December 2023.

Round of 16
The draw for the round of 16 was held on 23 February 2024, Union Saint-Gilloise were unseeded in the draw and was prevented from drawing Club Brugge as clubs from the same association can not play in this round.

Squad appearances and goals
! colspan=14 style=background:#dcdcdc; text-align:center|Goalkeepers

! colspan=14 style=background:#dcdcdc; text-align:center|Defenders

! colspan=14 style=background:#dcdcdc; text-align:center|Midfielders

! colspan=14 style=background:#dcdcdc; text-align:center|Forwards

! colspan=14 style=background:#dcdcdc; text-align:center|Players who have made an appearance this season but have left the club


 * }