When his Parma contract ends in four years, he will be 46.
The World Cup winner rejoined the club on a two-year deal last summer.
In the Italian top flight, he has played a record number of games.
This is a wonderful day for me and my family. I hope that the city and fans will be happy.
Parma is 13th in the 20-team Serie B after 26 matches and has played 23 league games this season.
"My return to Parma was linked to the relationships and the deep bond I have always had with this city," said Buffon, who announced the new deal in a news conference on Monday.
I would not have accepted this proposal if I had not believed in what the president had in mind.
I am positive about the future of this club. It is an exciting challenge for me.