This extends the former England under 20 back-rower’s stay at the club he originally joined ahead of the 2015/16 season.
Willis made his first XV debut at Sale in November 2016 in the Anglo-Welsh Cup, with his Premiership bow coming later the same month also against the Sharks.
Since then Willis’s rapid development has seen him first join the senior squad, before quickly forcing his way into Dai Young’s matchday 23 on a regular basis.
As a result, 17 of his 25 appearances have been registered this season, culminating in back-to-back man-of-the-match winning displays in the Anglo-Welsh Cup against Leicester and during Sunday’s Aviva Premiership win over Harlequins.
Jack Willis said: “I’ve been fortunate to get a few opportunities this year and I’m chuffed to extend my stay at Wasps.
“If you look at the coaching staff and players here it’s clear the club is going places.
“My focus now is on getting my head down and working hard to help us achieve the best things we can this season and in the future.”