The driver of the school mini bus, which was carrying 24 students, all in the age group of 8-10 years, was also killed in the mishap, Jalandhar Range's Inspector General of Police Gurpreet Deo said.
Police says around ten others were injured and have been moved to a nearby hospital.
"Seven students died on the spot, four died in hospital. The driver of the bus also died... The accident happened around 8 am," said Rajinder Singh, Superintendent of Police (Rural).
The accident happened on a highway near Jalandhar when the bus, belonging to Akal Academy, was on its way to school. It collided head-on with the truck.
The impact of the accident was so bad that the roof of the school mini bus was torn off and the vehicle was virtually reduced to a heap of metal.
A case of rash and negligent driving was registered against the truck driver, who fled after the accident.
Punjab Deputy Chief Minister Sukhbir Singh Badal expressed grief over the loss of lives and directed the district authorities to provide immediate medical aid to the injured.
Jalandhar deputy Commissioner Shruti Singh announced a compensation of Rs 1 lakh to the next of kin of those who died and free medical aid to the injured.