Following the fire report at 6am, firefighters and 10 fire engines put out the blaze in 30 minutes.
Abbot Phra Metheekornkavi said the fire reportedly stemmed from an unoccupied wooden building, jumped to a resident building whose monk occupant had left for the morning alms round, and then spread to another unoccupied building. The heat also damaged a fourth nearby building.
Police suspect a short circuit caused the fire. Forensic officers will conduct a more detailed inspection of the scene, they said.
The fire damages were being assessed as of press time.
Wat Senasanaram, located behind the Chantharakasem National Museum (the former Front Palace), is a royal temple built in the Ayutthaya era on the site of a former ancient temple called Wat Sua (Tiger Temple).