The human rights group pointed the finger of blame mostly at U.S. forces, saying that of the 140 civilian deaths it investigated between 2009 and 2013, none were prosecuted by the American military.
In the report released today, Amnesty did note that the majority of innocent casualties in more than 12 years of warfare have been caused by the Taliban and other insurgent groups.
But Richard Bennett, the group's Asia-Pacific director, says there is evidence that suggests some of killings attributed to NATO forces were deliberate and could constitute war crimes.
When civilian casualties are reported and NATO announces an investigation, Bennett says Afghan witnesses are rarely interviewed or even contacted.
The report makes no mention of Canadian troops, who fought a five-year guerilla war in Kandahar, but does say Canada's military justice system has more civilian oversight and control, which puts it in a better position than the U.S.