The Norway international has agreed a two-year extension to his current contract, with an option for a further year.
Hangeland arrived from FC Copenhagen in January 2008, helping the club to Premier League survival that term, and has gone on to make 236 appearances.
"I'm delighted," he told the club's official website.
"It's taken a long time but we're there now. I hope the club is happy; I'm certainly really happy to have signed.
"I've loved my time at Fulham. It's been a little over five years and I've felt right at home from the beginning. I couldn't really see myself leaving so to know I'm here for a few more years gives me a great feeling."