Spanoulis won the 2015–16 season's Greek League championship. In game 2 of the 2015–16 Greek League Finals, against Olympiacos' arch-rivals, Panathinaikos, Spanoulis hit a game-winning buzzer-beating 3 pointer. In game 3 of the Greek League Finals, he scored 11 points in the last 3 minutes and 1 second of the 4th quarter, to seal the victory for his team. In game 4 of the Greek League Finals, held at Nikos Galis Olympic Indoor Hall, Olympiacos won in the game's second overtime period, after Spanoulis hit another game-winning 3 point field goal, with 1.9 seconds remaining in the game. He was subsequently named the 2016 Greek League MVP, and the 2016 Greek League Finals MVP.