"Two of our own have made the ultimate sacrifice, and we celebrate their lives and mourn their deaths," said Governor General David Johnston.
In his eulogy, Prime Minister Stephen Harper told mourners that the war memorial is a reminder that "freedom is never free. It has been earned by the soldier and then donated to all of us."
"Most of us can never truly understand the significance to a soldier of the simple act of standing reverently on guard at that place," Harper said.
"Corporal Cirillo, who felt the calling of a soldier when he was just a 13-year-old cadet, he understood. He knew what he was protecting and what he was preserving. He died protecting and preserving it."
Harper was to meet later in the day with US Secretary of State John Kerry, who travelled to Canada to show Washington's solidarity with Ottawa. Kerry placed a wreath at the war memorial in Cirillo's honour.
Secretary of State John Kerry, U.S. Navy Attache Capt. Charles J. Cassidy and Canadian Foreign Minister John Baird. Photo / Sean Kilpatrick
Canada has remained defiant in the wake of the attacks and threats in militant broadcasts over its role in the US-led campaign against Islamic State jihadists.
Some Canadians have travelled to the Middle East to join the group.
Police say the two attackers were tempted by the prospect of waging war in Syria, another IS stronghold.
Zehaf-Bibeau, 32, was described as a petty criminal who was estranged from his family and struggled with a drug addiction.
The assailant in the Quebec attack, 25-year-old Martin Couture-Rouleau, had been on a watch list of suspected Canadian extremists before he used his car as a weapon to run over two soldiers in Quebec on October 20, killing one of them before being shot dead by police.
In July, he was barred at the last minute from leaving for Turkey, a popular entry point for would-be jihadists looking to fight in Iraq and Syria.
Police seized Couture-Rouleau's passport as he sought to board an airplane in Montreal, but did not have enough evidence to arrest him.
- AAP