Jason Gilbert Giambi (pronounced /dʒiˈɑːmbi/; born January 8, 1971 in West Covina, California) is a Major League Baseball designated hitter and first baseman currently with the Colorado Rockies. He is nicknamed "The Giambino," " Giam - boom," "The Big G," and "The Dancing Bear."

He was the American League MVP in 2000 while with the Oakland Athletics, and is a five-time All-Star who has led the American League in walks four times, in on base percentage three times, and in doubles and in slugging percentage once each, and won the Silver Slugger award twice. He attended Long Beach State.

Giambi is known to have taken performance-enhancing drugs during his career, for which he has publicly apologized.