The incident took place in the eastern province of Ghazni.
The vehicles were travelling on a highway in Ghazni, Afghanistan, when they collided.
Jawid Salangi, a spokesman for the governor of Ghazni said two buses carrying 125 passengers from Kabul to Kandahar crashed into the tanker.
The fuel tanker was travelling in the opposite direction.
A massive fire broke out which quickly engulfed all three vehicles.
Afghan army units were rushed to the scene of the accident in Moqor district and managed to save some passengers.
However, many of the injured were in a critical condition