Lynch made his debut in Round 15 against Geelong and played every game for the rest of the season following his debut.
“Brad has been a tremendous story of persistence and commitment, and it was great to see him make his mark at AFL level this season,” Bulldogs’ General Manager of List and Recruiting, Sam Power told the club’s website.
“We clearly believe Brad has an exciting future in the game, and we’re delighted to see him commit for a further two seasons.
“Along with some of our other exciting young talent, we’re eager to see how Brad will continue to improve in the coming years.”
Lynch was the 11th pick by the Bulldogs in the 2015 rookie draft and played in Footscray’s VFL premiership in 2016.