The international community has endorsed sweeping Afghan government plans to take responsibility for security by 2014.
President Hamid Karzai's government also wants to begin peace efforts to end nine years of war and take greater control of aid projects.
UN Secretary General Ban Ki-moon and US Secretary of State Hillary Clinton led about 80 organisations and countries at a key conference in Kabul today.
The aim of the conference was to put Afghanistan on the road to stability and allow foreign troops to gradually pull out.
Mr Karzai is under intense Western pressure to crack down on corruption, make better use of billions of dollars of aid money and stop the Taliban insurgency.
He delivered a keynote address seeking to convince the international community he was capable of assuming responsibility for security and cleaning up government.
The final communique from the conference backed Mr Karzai's call for Afghan security forces to 'lead and conduct military operations in all provinces by the end of 2014,' allowing foreign troops to start pulling out.
Mr Ban said the communique reflected the determination of the international community 'to stay engaged for the long-term'.
He added: 'Now we must focus all our energies on making this vision a reality.'
Mrs Clinton described the plan as 'comprehensive' and said the conference marked a 'turning point'.
British Prime Minister David Cameron said plans for a transition in four years were 'realistic'.
NATO chief Anders Fogh Rasmussen told the conference that the alliance would remain in Afghanistan even after Afghans take responsibility for security.
The scale of the challenge was made clear by the thousands of Afghan troops, backed by NATO forces, who put Kabul under security lockdown to prevent any Taliban attack on the conference.
Mr Karzai said the international community had committed enough money to see Afghanistan through the next three years.
The International Monetary Fund also announced a €97m loan for Afghanistan to help the country move towards financial sustainability.
