Meunier had joined Turkish side Trabzonspor in February from Borussia Dortmund. He previously won the Ligue 1 title three times with Paris Saint-Germain and was in the Belgium squad that finished third at the 2018 World Cup.
"Lille was the perfect choice from a sporting and family point of view. With its proximity to Belgium, it's like being at home," Meunier said in a statement.
"My experience in the various European Cups will enable me to coach the youngest members of the dressing room and ensure that they're 100% focused on the club's sporting success."
Lille will be in the Champions League qualifiers after finishing fourth in Ligue 1 last season. They begin their league campaign at Reims on August 18th.