The association issued a statement saying Alan Borovoy died Monday, but did not provide cause of death. He was 83.
Association Executive Director Sukanya Pillay says Borovoy once led the organization and championed human rights causes for more than 40 years.
Pillay says Canada owes Borovoy an immense debt and pledges the association will honour his memory by continuing to fight for fundamental freedoms and human rights.
The Toronto lawyer served as the association's general council from 1968 to 2009, during which time he tackled issues ranging from police race relations to free speech.
He was the author of five books as well as a biweekly column in the Toronto Star, and he was made an officer of the Order of Canada in 1982.
"We will greatly miss him, his brilliance, his generosity, his irreverent humour, and the passion and dedication to equality and justice that was his life's work," Pillay said in the statement announcing his death.