The victim, identified as Siriporn Srichai, drove her motorcycle on the Ban Cho Ba Ngae-Ban Ta Bing Ting Ngi Road in Lubo Yilai subdistrict of Mayo district when she was approached by two men on another motorcycle. After the shooting, the killers then poured petrol on her and set her alight.
She was reportedly on her way to work at Tabingtingi School.
Investigation is under way to collect evidence to identify the suspect.
170 school teachers have been killed in the decade-long insurgency.