The incident, caused by speeding, took place late Saturday near Layyah city when the driver of the van lost control and collided with a trailer.
The passengers of the van were from the same family who were going to attend a marriage ceremony.
‘At least 11 people - that include three women, two men, five girls and a minor child - were killed in the accident,’ local police official Muhmmad Boota told dpa.
Another 18 people, including eight children, were injured and taken to Nishtar Medical Hospital Multan for treatment, he added.
Fatal traffic accidents are common in Pakistan due to poor roads, badly maintained vehicles and reckless driving.