The attacking midfielder returns to his former club from Bayern Munich, having previously departed the club in 2013 to move to the Allianz Arena, where he struggled for game time.
Borussia Dortmund has announced the signing of Mario Gotze from Bayern Munich.
The Germany international, who scored the winning goal in the 2014 World Cup final, had previously left Dortmund for the Bavarians but has now re-joined Thomas Tuchel's side.
Gotze departed the club in somewhat acrimonious circumstances in 2013, having scored 31 goals in 116 matches for the club after his debut in 2008.
Some fans subsequently claimed that the 24-year-old would not be welcomed back to the club, but the deal has now been confirmed by both sides, with Gotze signing a four-year contract until 2020.