The move brings to a close the 33-year-old left back’s eight-and-a-half year stint at Old Trafford.
“After a great deal of thought I have decided the time is right for me to leave Manchester United,” the player told United’s website.
“It is the biggest decision of my career as this club is, and will always remain, in my heart.”
A Juventus statement read: “Juventus football club can today announce that Patrice Evra has signed a two-year contract with the club after a fee of £1.2million, to be paid in two separate instalments, was agreed with Manchester United.
“A further payment of £300,000 will be made to Manchester United in the event of Juventus qualifying for the 2015/16 Champions League.”
Evra was part of the France side that made it to the World Cup quarter-finals. four years ago he was the captain who led a team protest.