The following timeline presents an overview of critical events in the development and history of Canadian military involvement in the "war on terror" and subsequent military efforts in Afghanistan.

2001

11 September	Terrorists attack the World Trade Center in New York City and the Pentagon in Washington, killing nearly 3,000 people including 24 Canadians. North American airspace is shut down, and hundreds of international flights are diverted to Canadian airports.
14 September	80,000 attend a rally on Parliament Hill in Ottawa.
20 September	US President George W. Bush declares that the al-Qaeda terrorist group is responsible for the 9/11 attacks, and demands that the Taliban surrender al-Qaeda leader Osama Bin Laden. Canadian Minister of National Defence Art Eggleton authorizes Canadian forces to participate in 9/11 operations.
2 October	The North Atlantic Treaty Organization (NATO) invokes Article 5, the collective defence provision of the North Atlantic Treaty, for the first time in its history. President Bush initiates Operation Enduring Freedom, the coalition operation against the Taliban and al-Qaeda in Afghanistan.
5 October	Canadian Prime Minister Jean Chrétien meets with President Bush, who requests a Canadian contribution to the multinational coalition in Afghanistan.
8 October	Coalition air forces begin attacks against targets in Afghanistan. Defence Minister Eggleton announces the beginning of Operation Apollo, Canada's contribution to the "War on Terror".
17 October	Three Canadian warships leave Halifax for the Arabian Sea.
22 December	The United Nations-backed Afghanistan Transitional Authority, headed by Hamid Karzai, is inaugurated in Bonn, Germany.

2002

2 February	The first Canadian soldiers arrive in Afghanistan.
13 March	500 troops participate in the Canadian military's first battalion-level helicopter air assault against suspected Taliban positions.
17 April	Friendly fire from American jets kills four Canadian soldiers.
3 May	Canadian soldiers search Osama Bin Laden's last known location in the mountains of Tora Bora.
August	The first mission to Afghanistan ends as the Canadian Battle Group leaves Kandahar and begins its return to Canada.

2003

12 February	Canadian Minister of National Defence John McCallum commits 1,500 soldiers to head the United Nations-mandated, NATO-led International Security Assistance Force (ISAF) in Kabul.
2 October	A minestrike kills two Canadian soldiers outside Kabul.

2004

26 January	Canadian soldiers raid two compounds in Kabul, arresting an alleged terrorist suspected of planning the minestrike.
27 January	A suicide bomber targets a Canadian convoy in Kabul, killing one Canadian soldier and wounding three others.
9 October	Canadian soldiers provide security in Kabul for Afghanistan's first presidential elections.

2005

17 May	Canadian Minister of National Defence Bill Graham announces that Canadians will return to Kandahar in August 2005 to take over a Provincial Reconstruction Team (PRT).
August	Approximately 250 Canadian soldiers take over the Provincial Reconstruction Team based in Kandahar.
18 September	Canadian soldiers provide security for parliamentary elections in Kandahar.
18 October	Canada's commitment to the International Security Assistance Force (ISAF) in Kabul ends.
November	Soldiers close Camp Julien, the Canadian base in Kabul.
12 December	A roadside bomb wounds three Canadian soldiers outside of Kandahar.

2006

15 January	A suicide bomber kills Canadian diplomat Glyn Berry and badly wounds three soldiers in Kandahar city.
February	Over 2,000 Canadians join United States-led counter-insurgency and combat operations in Kandahar province. Renewed Taliban activity in the area leads to heavy fighting throughout the spring and summer of 2006, and many Canadian casualties.
17 May	Captain Nichola Goddard is killed west of Kandahar. She is the first female Canadian soldier killed in combat in Canadian history. Members of Parliament approve an extension of the Canadian deployment to Afghanistan until 2009.
31 July	ISAF assumes responsibility for operations in southern Afghanistan; Canadian forces come under NATO command.
Summer/Fall	Canadian and NATO soldiers face a renewed Taliban offensive in Kandahar and Helmand provinces in southern Afghanistan. Some Canadians call this "The Battle of Panjwai", after the unsettled Panjwai region, west of Kandahar city.