Commissioner Jeffrey Orridge made the announcement Thursday at the league's Inside The CFL event.
"The CFL’s partnership with TSN and RDS has been central to our growth and momentum and we look forward to working together to reach new and even bigger audiences," Orridge said.
The present deal was scheduled to expire following the 2018 season.
In March 2013, the CFL and TSN agreed to a five-year broadcast agreement that was reportedly worth $43 million annually, starting in 2014. That was more than 2 1/2 times the previous five-year agreement, which was worth $15 million a year.
Under terms of the extension, TSN and RDS continue to hold exclusive media rights to all CFL games, including the Grey Cup. In addition to broadcast and digital rights, the deal features exclusive radio rights to the Grey Cup for Bell Media’s Grey Cup Radio Network.
"The CFL continues to rank as one of Canada’s leading sports properties," said Phil King, president, CTV, Sports, and Entertainment Programming. "With many new stadiums opening across the league and a new era beginning in Toronto, this is truly an exciting time for the CFL.
"We are thrilled to extend our partnership and to continue to shine the spotlight on this beloved Canadian sports institution for years to come."
Last week, the Toronto Argonauts were sold to Bell Canada and Larry Tanenbaum, the chairman of Maple Leaf Sports and Entertainment. The CFL franchise is scheduled to begin play at BMO Field next season.
The 2015 regular season kicks off June 25 with the Ottawa Redblacks visiting the Montreal Alouettes and will culminate with the 103rd Grey Cup game Nov. 29 in Winnipeg.