The 20-year-old joins from domestic rivals Utrecht after starring for under manager Erik ten Hag, registering seven assists in 31 games to help the club finish in fourth place.
Feyenoord technical director Martin van Geel revealed the club’s delight in acquiring the sought after Morocco international ahead of Ajax Amsterdam, for a modest fee of €4million.
“Sofyan is a very talented player, with great physical qualities alongside his footballing ones,” he told the club’s official website. “That among other things is why we feel he is a player who fits Feyenoord.
“We are certain that he adds to our squad and that he can improve hugely in the future.”