Mansoor was coming to Lahore from Islamabad on his car when it skidded off the road and overturned near Faizpur, a JuD statement said yesterday.
He died on the spot, while his gunman and driver suffered serious injuries. They were shifted to a hospital in Lahore.
Mansoor, the chairman of Tehreek-e-Azadi Jammu and Kashmir, was considered to be very close to Saeed, the mastermind of the Mumbai terror attack.
JuD chief Saeed will lead Mansoor's funeral prayers.
Mansoor, a native of Jia Baga, was also part of Hurmat-e- Quran and Hurmat-e-Rasool movements.