The accident occurred near Sheikhupura city early this morning while the bus was going from Lahore to Faisalabad.
Karamat Ali, an official of the state-run rescue service, told PTI that several women were among the dead.
Ali said a passenger told rescue workers that the bus hit an electricity pole after the driver fell asleep at the wheel.
Police officials said the bus was speeding at the time of the accident. Local residents and rescue teams took the injured to a hospital in Sheikhupura.
Road accidents are common in Pakistan because of poor infrastructure and disregard of traffic laws.
Twenty-four people were killed on March 16 when a bus carrying soldiers fell into a ravine in northern Pakistan.