Justin Irvin Upton (born August 25, 1987 in Norfolk, Virginia) is an American Major League Baseball right fielder for the Arizona Diamondbacks. He was selected first overall by the Diamondbacks in the 2005 Major League Baseball Draft. Justin is considered a 5 tool player, acknowledged for having hitting prowess as well as solid fielding capabilities. Justin and his brother B.J. of the Tampa Bay Rays are the only brothers in Major League Baseball to ever be selected in the number one and two slots of a first round draft.

He was previously an all-district shortstop for Great Bridge High School in Chesapeake, Virginia, and was awarded the AFLAC National High School Player of the Year Award. He is also the brother of Tampa Bay Rays center fielder B.J. Upton, who was taken at the number two pick in the 2002 draft.

In his first professional season he played for Class-A South Bend Silver Hawks. He began 2007 with the Class-A Advanced Visalia Oaks, but was promoted to the AA Mobile BayBears after hitting .341 with 5 home runs for the Oaks in April.