07:30 12 Aug 2019
The Belgium international will spend 12 months on-loan at the Belgium Pro League club from French Ligue 1 side Monaco.
Chadli, 30, made a mere 22 appearances for Monaco across all competitions in the 2019/20 season, in what was a difficult campaign for the club which almost ended in relegation.
The former Tottenham Hotspur and West Bromwich Albion winger started his youth career at Standard Liege in Belgium before making a name for himself at FC Twente.
Chadli joined Monaco on a three-year deal from West Brom last August, after netting just one goal in eight games as the Baggies suffered relegation from the English Premier League.
Anderlecht will have an option to buy Chadli at the end of the season. He will link up with former Manchester City duo Vincent Kompany and Samir Nasri at the record 34-time Belgian champions.
Chadli has scored six goals in 56 games for Belgium.