The deal carries an average annual value of $7.875 million and runs from 2022-23 to 2029-30.
Suzuki, 22, is coming off a 41-point campaign in the NHL's shortened 56-game 2020-21 season. During Montreal's run to the Stanley Cup Final, he produced 16 points in 22 games.
"We are very happy to secure Nick's services for the next eight seasons," said Canadiens general manager Marc Bergevin in a statement.
The London, Ont., native has developed into a franchise-calibre centreman since joining the Canadiens at the beginning of the 2019-20 NHL season.
A 13th overall Golden Knights draft pick in 2017, Suzuki was Montreal's key acquisition in a trade that sent Max Pacioretty to Vegas.