The 42-year-old was riding a motorbike to work at an elementary school in the Mayo district of Pattani province when she was attacked.
"Gunmen shot her and set fire to her body," a local police officer said by telephone.
She was the 171st education worker to be killed during the decade-long conflict in Thailand's Muslim-dominated deep south near the border with Malaysia.
The insurgency has claimed more than 5,900 lives -- the majority of them civilians -- in near-daily attacks including shootings, bombings and even beheadings.
AFP