Mark Bisset, a former managing editor of the Orillia Packet and Times, said Dennis died Wednesday morning.
Bisset recalled Dennis, who had retired to Orillia after a career as an educator, adviser and consultant, as a "brilliant man" with "boundless energy."
"He was just such a clever, engaging guy," said Bisset.
Dennis was co-author of an influential 1968 report on Ontario's education system entitled "Living and Learning."
Also known as the Hall-Dennis report, it was considered controversial for its time, calling for an end to rote learning and corporal punishment.
Dennis, an adviser to the Conservative government of the day, wrote the report with Supreme Court Justice Emmett Hall.
"The committee recognizes the need for pupils to learn that behaviour has its consequence, but can find little to defend, solely as means of correction, such punishments as the writing of lines, isolation, detention after school, extra work, sarcasm, and ridicule," the report read.
"The committee is opposed to the use of the strap as a form of correction, and therefore strongly recommends the abolition of corporal punishment from our schools."
Presented to the Ontario legislature the year before Neil Armstrong became the first person to walk on the moon, the report noted: "like the men who make the initial landing on the moon, our children must be thoroughly prepared for a destination whose features no one knows at first hand."
Among his many awards, Dennis was made an officer of the Order of Canada in 1971 in recognition of his service to education. He also received the Order of Ontario.
He was the author of several books including "The Learning Circus" and his memoirs "Marching Orders."
In his book "Treasure Chest of Muskoka Memories," Lloyd recalled growing up in the Muskoka region of Ontario in the 1920s and '30s.