Details of the shooting in the Rue So district were not immediately available but police suspect Muslim fighters were behind it also.
Violence has escalated in recent weeks in southern Thailand where a Muslim separatist movement has re-emerged after more than 20 years of relative peace.
Teachers are often targeted by separatists, along with police and civil servants, all of whom are viewed by the fighters as collaborators with the government.
Clashes in Yala, Narathiwat and Pattani, all Muslim-majority provinces in the Buddhist country, have claimed more than 1,900 lives since 2004.
Surayud Chulanont, Thailand's prime minister, has pledged to end the violence.
But his visit to the region on Saturday – in which he reiterated his commitment to forging a peaceful solution to the unrest – coincided with the ambushing of police patrols and torching of a government school by suspected separatists.