Sokolowski has signed a deal that will keep him at the club until 2012.
Viking sports director Egil Ostenstand was delighted with the new signing.
He said: “Tomasz is a superb player that will add quality and experience from almost 150 games in the Tippeligaen.”
The 23-year-old has also been linked with German side Kaiserslautern in recent weeks.
