Gaoteote is a former top recruit for the Trojans, ranking 18th overall on the ESPN 300 in 2018 and rated as the top linebacker.
He announced in December he was leaving USC.
Gaoteote amassed 58 tackles in eight games in 2019. He made two starts last season in a shortened campaign before suffering a season-ending concussion in November.
Texas has been the destination of a number of transfers this offseason as it enters its first year under new head coach Steve Sarkisian. The Longhorns also landed former Alabama defensive lineman Ben Davis and New Mexico State linebacker Devin Richardson.