Kanwara Khrueangphathi, 45, was found dead in front of her house in Siri Garden 2 housing estate in Muang district. He husband Nithithon Nabamrung's body was also found at the house.
Both were teachers at Ban Nongta Kai Nongmek School. They had one child together.
Neighbours told police they heard a quarrel in the house before Nithithon shot his wife in the head.
He then shot himself in the head.
The neighbours said the couple argued often in recent weeks.
Police suspect their quarrels were related to problems caused by adultery or debts.