Guillermo Andrés Rivera Aránguiz (American Spanish: [gi'?e?mo an'd?ez ri'ße?a a'?a?gis]; born 2 February 1989, in San Felipe, Chile) is a Chilean professional tennis player.
Rivera will be eligible to play in Davis Cup competitions for Chile in March 2011 against the United States.
He made his debut in Davis Cup singles for disputing the fifth point of the series against the United States, facing John Isner, losing him 3–6, 7–6, 5–7.