Giedrius Gustas (born March 4, 1980) is a Lithuanian professional basketball player. He plays mainly at the point guard position, but he can also play at the shooting guard position. He is 1.90 m (6 ft 2 ¾ in) tall and he weighs 86 kg (190 pounds).
In 2008, while playing with the Latvian Basketball League club Barons LMT, he won the EuroCup championship, and he was named league's the Final Four MVP. In 2009, he joined the HEBA A1 club EKK Kavala.
He has been a member of the Lithuanian national basketball team. He has played at the 2006 FIBA World Championship. He has also played at the 2003 European Championship, where he won a gold medal, the 2005 European Championship, and at the 2007 European Championship, where he won a bronze medal.