Giannis Giannoulis (alternate spellings: Gioannis,[1][2] Yannis,[3][4] Ioannis,[5][6] Yiannis (Greek: Γιάννης Γιαννούλης; born June 5, 1976) is a Greek-Canadian former professional basketball player.

A failed drug test, at the end of the 2001–02 season, cost Giannoulis a ban from all European continental competitions for 2 years, which was a great blow to his career.

He also played with the Huntsville Flight (later known as the Canton Charge), of the NBA D-League, during the 2002–03 season, after joining the club in February 2003.

After playing with the Flight in just two games,[11] Giannoulis requested to be waived from the D-League team, and then returned to the Greek League.

With Greece's junior national teams, he played at the 1993 FIBA Europe Under-16 Championship, where he won a gold medal.

[12] After being banned from continental competitions for two years, due to a failed drug test, he was removed from the senior Greek national team and he was never recalled to it after that.