The 34-year-old, who is widely regarded as one of the best stoppers in world football, has admitted his delight at penning terms on a fresh contract.
"I remember my first day and the fact that I was asking myself if I was up to the standard of a club like Juventus. My rapport with the fans has been important. I also enjoy a good relationship with the management and coaching staff," he told the club's official website.
"I would have turned down offers from other teams. For me, Juventus has become a way of life. We want to reclaim the Italian title. We've shown we're back as a competitive force in Europe. That's what matters."
Juventus currently sit top of Serie A.