The deal runs through the 2020 season. Financial terms were not announced, but Fox Sports' Ken Rosenthal reports Simmons will receive $58 million over the life of the deal.
Simmons, 24, hit .248 with 17 home runs and 59 RBIs last season for the Braves, but is better known for his defense.
Simmons earned his first career Gold Glove Award last season, when he led all Major League players with 499 assists. He also had 41 defensive runs saved last year.
The Braves have been active this offseason locking up their young talent, signing first baseman Freddie Freeman to an eight-year deal worth $135 million earlier this month.
The Braves have agreed to terms with SS Andrelton Simmons on a seven-year contract. The deal runs through 2020. — Atlanta Braves (@Braves) February 20, 2014