The 21-year-old is a versatile forward that has played 33 times for Wasps in a variety of positions including lock and blindside flanker.
Wasps director of rugby Dai Young has declared that he is delighted to secure Launchbury's services on a long-term basis.
He told the club's official website: "This is fantastic news for us and it is a huge signing for the club.
"It gives a real shot in the arm to all of our players and coaches as it's a vote of confidence in what we are trying to do here.
"I am sure our supporters will be over the moon that someone of Joe's quality has signed on for the foreseeable future."
Launchbury will win his first international cap this weekend if he makes an appearance in the opening Autumn Test against Fiji at Twickenham.