The announcement comes just ten days after Prandelli quit as coach of Italy's national team after it failed to make it past the group stage of the World Cup in Brazil.
Following speculation of his move to Galatasaray, which came second in the Turkish Super League last season, the club made the official announcement on Thursday.
Prandelli is set to begin coaching the team on Monday, a message posted on Galatasaray’s Twitter account said. He will replace fellow Italian Roberto Mancini, who left the club in June after just one season.
Ünal Aysal: Prandelli Pazartesi günü takımın başında olacak.— Galatasaray SK (@GalatasaraySK) July 3, 2014
Before taking the Italy post in 2010, Prandelli had led a 20-year career coaching squads including Fiorentina and Parma. During his career on the pitch he played for Juventus and a number of other Italian teams.