The bus with more than 40 passengers on board was heading to Panjgur from Karachi collided with an oil tanker coming from the opposite direction.
The crash reportedly took place on Monday in Balochistan's Lasbela district, while 26 passengers lost their lives.
At least 10 passengers were wounded and two vehicles burned with the spread of oil in the tanker.
In August, a tanker collided with a bus in the country killed 18 people.
ILKHA