The 26-year-old, who has struggled with a shoulder injury this season, has penned a two-year extension at the Select Security Stadium.
O'Carroll made the move to Widnes from Hull FC two years ago.
"I'm really pleased to sign the contract," he is quoted as saying by Sky Sports News. "Everyone talks about the club moving forward, which it is, but from a player's point of view the progress the club has made in just the last two years has been massive."
Widnes continue their Super League campaign on Sunday when they travel to Hull Kingston Rovers.