| Conflict: | Operation Accius |
| Partof: | the War in Afghanistan (2001–2021) |
| Date: | November 28, 2002 – 2004 |
| Place: | Afghanistan |
| Combatant1: |  Canada |
| Combatant2: | |
| Commander2: | Osama bin Laden |
Operation Accius is the Canadian military's contribution to the civilian-led United Nations Assistance Mission in Afghanistan (UNAMA). On November 28, 2002, the Minister of National Defence John McCallum announced that a senior Canadian Forces officer by the name of Lieutenant Colonel David Ross would be deployed to Afghanistan (until June 2004) to serve as the military advisor to UNAMA.
The UNAMA Military Advisory Unit comprises officers of the rank of Lieutenant-Colonel or equivalent from several nations, under the command of a Brigadier-General. Using the Kabul UNAMA office as a main base, the military liaison officers have several tasks, the most important of which is to provide timely military advice to the Kabul-based Special Representative to the Secretary-General. They routinely work at UN regional offices outside Kabul.
The prime concerns of the military liaison officers are disarmament, demobilization and reintegration (DDR), which are handled by the UN through the "Afghanistan New Beginnings Programme." The DDR initiatives of the Afghanistan New Beginnings Programme will affect 100,000 soldiers, providing many with skills counselling and, sometimes, placement in non-military jobs. The military liaison officers help identify soldiers to be demobilized, and work with a Japanese-led International Observers' Group that ensures the process is fair, accurate and timely. DDR in Afghanistan is expected to take three years. The military liaison officers deal with many organizations, agencies and individuals operating in Afghanistan, including the following: