Bennett, 18, has put pen to paper on a new four-year deal, keeping him at the club until the summer of 2018.
A product of the club's academy, Bennett became Derby's youngest-ever player at the age of 15 years and 99 days in October 2011, and has gone on to make 32 first-team appearances.
Derby head coach Steve McClaren is delighted to have secured the future of Bennett who was named Championship Scholar of the Year at the Football League Awards in March.
"Mason Bennett is an exciting young talent and we’re pleased to announce that he has signed a new contract," McClaren told the club's official website.
"He is one of a number of players that our Academy has produced in recent years and he has a lot of potential to work with and develop.
"Mason had a brief loan spell at Chesterfield last season and we’ll see if we can do something similar this year, which will be another important part of his development."
Bennett, who scored his first league goal for the club in last season's 5-1 win over Millwall, has represented England at U16, U17 and U19 level.