The fire was brought under control by three firefighting units
Shamsunnahar, 37, taught at Dhaka's Agargaon Tawhid Laboratory School.
Her husband Shajahan Siraj, who works in a private company, has also been injured in the attack.
Siraj was recently transferred to Noakhali. He was moving there in a covered van with his wife and two sons.
Sudharam police OC Anowar Hossain said strikers hurled stones at the van hitting Shamsunnahar on the head.
Doctors declared her dead when she was rushed there around 10am.