Greggory William Olson (born October 11, 1966) is an American former professional baseball player, coach, scout and television sports commentator.

During Olson's major league tenure, he also played for the Atlanta Braves, Cleveland Indians, Kansas City Royals, Detroit Tigers, Houston Astros, Minnesota Twins, Arizona Diamondbacks and Los Angeles Dodgers.

[citation needed] In the state championship game of his senior year, Olson threw a no-hitter.

A reliever, he threw what baseball historian Sheldon Stewart referred to as a "blazing fastball and devastating curve".

Olson also set an American League rookie record with 27 saves, and had a 5–2 mark with a 1.69 earned run average (ERA) and 90 strikeouts in 85 innings.

Selected to the All-Star team in 1990, Olson set a club record of 37 saves during the season and collected 31 and 36 in the next two years.

He finished with 29 saves and a career low 1.60 ERA, but Baltimore opted not to take a risk with him and signed Lee Smith as their new closer.

After pinch-hitter J. T. Snow walked to load the bases, manager Buck Showalter ordered Olson to intentionally walk Barry Bonds, forcing home a run, and bringing up Brent Mayne, who worked the count full before he lined to right field for the third out.