Hunter, 23, was entering the final year of his contract with a base salary of $1.9 million. The team did not disclose terms of the extension.
In three seasons with Minnesota, Hunter has 25.5 sacks. In 2017, he had seven sacks but tallied a career-best 12.5 in 2016.
The Vikings led the NFL in total defense last season, allowing just 275.9 yards per game.