The Northern Ireland centre-back came through the United academy after signing as a youngster and has made 141 appearances since his debut in 2007.
Evans had spells on loan with Royal Antwerp and Sunderland but has been a regular in the United squad since the end of his second stint at the Stadium of Light in 2008.
He told the club's official website: "I'm delighted to sign my new contract.
"I am so proud to play for such a great club, and there's no better feeling than playing football in this team and winning games.
"I have always felt that this is the right club for me. Even when I was nine or 10 years old back home in Northern Ireland, clubs asked me to go on trial but I didn't go because I knew that Manchester United was the place I wanted to play football.
"I have come through the Academy here and developed as a player with the help of all my team-mates, the manager and the coaching staff. I would love to play here throughout the rest of my career."
United boss Sir Alex Ferguson said: "Jonny has risen through the ranks to become an integral part of the first-team squad.
"He has developed into a top player for us and has scored a couple of important goals this season too. I am delighted he has signed a new contract."
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