Olson completed 28 of 38 passes and the Bruins (3-0) scored 17 points off three Sooner fumbles to deal Oklahoma -- a team which has appeared in each of the last two national championship games -- its second defeat in three weeks.
UCLA, which is off to its best start since winning its first six games of the 2001 season, held Sooners' star running back Adrian Peterson to 58 yards on 23 carries.
Oklahoma (1-2), off to its worst beginning in the Bob Stoops era, showed some life offensively after struggling through its first two outings.
The Sooners managed 398 total yards and received a strong performance by redshirt freshman quarterback Rhett Bomar. However, OU's vaunted defense was shredded repeatedly by Olson and yielded 21 fourth-quarter points which sealed its fate.