Garrett Andrew Olson (born October 18, 1983, in Fresno, California) is a Major League Baseball pitcher for the Seattle Mariners.
Olson attended Buchanan High School in Clovis, California. He played for the Anchorage Bucs in the Alaska Baseball League in 2004, going 7–0 with a 0.88 ERA, and was a Summer League First-Team All-American starting pitcher.
He attended Cal Poly-San Luis Obispo for college, where in his last year he was 12–4 with a 2.71 ERA. In 2005, he was a Big West Conference All-Star starting pitcher. Olson is just a few credits short of an engineering degree.