The Lightning did not disclose terms of the deal, but reports say the deal is worth $37.5 million, NHL.com reports.
In the 2010-11 season, Stamkos recorded 45 goals and 91 points. Stamkos added 13 points in the playoffs, and showed his toughness by returning to Game 7 of the Eastern Conference Final after a Johnny Boychuk shot hit Stamkos in the face and broke his nose.
"Steven is extremely important to this franchise and is part of the foundation of our hockey team," Lightning general manager Steve Yzerman said. "We are very pleased to have him signed and look forward to seeing him in a Lightning uniform for years to come."