Nuntana Kaewchan, 51, of Banta Kamcham School was shot in the face and torso. She was taken to a nearby hospital but succumbed to her injuries there.
Police said Nuntana was driving her car to the funeral of a police officer. She was about 100 metres from her school when two men hiding near a fence emerged and sprayed the car with bullets. The gunmen then escaped into the nearby bush.
Five bullet casings from an M16 rifle and 15 spent shells from a 9mm pistol were found at the scene, police said.
After the attacks, Banta Kamcham and other nearby schools abruptly suspended classes. Soldiers escorted teachers and students to prevent more attacks.
Nuntana is the 154th school employee to fall victim to violence in the South.