The England Under-21s international has put pen-to-paper on a new contract at Old Trafford to keep him at the club until June 2017, with the option of a one-year extension.
The 20-year-old came through the academy at United, making his senior debut for the club in the opening game of the Premier League season, and he has gone on to make ten further appearances for the Red Devils.
"I am delighted that Tyler has signed a new contract. He is another young player that has risen through the academy system to break into the first-team squad this season," United boss van Gaal told ManUtd.com.
Van Gaal is 'delighted' to have secured Blackett's future
"Tyler has great potential and I believe he is at the right club to continue his development and progression to become a great defender."
After penning his deal, Blackett added: "I'm thrilled to have signed my new contract. I have supported United all my life and have been here since I was eight-years-old.
"To come through the academy and make my debut this season was a dream come true. I want to keep improving within the first-team squad with the help of the manager, coaches and the players around me."
The youngster appeared for Gareth Southgate’s Young Lions during the 3-0 win over Moldova in September and has previously been capped at U16, U17, U18 and U19 level.
