The 23-year-old has signed a one-year extension which ties him to the club until the summer of 2017.
The deal should see Jack stay at Pittodrie for at least another season while still giving the club the option of gaining transfer income on the highly-rated Aberdeen-born player, who has made almost 180 first-team appearances.
Manager Derek McInnes told the club’s official website: “We are all delighted Ryan has committed to the club until the end of season 2016/2017. It shows real intent from Ryan to play his part in a successful Aberdeen team.
“It also demonstrates the club can hold on to its good players as well and hopefully Ryan can continue to impress in an Aberdeen shirt next season.”