A fire broke out in a document filing room at Rajabhat Suan Sunantha University early on Thursday.
Police said no one was injured in the fire.
A room on the fourth floor of the office building of the university's rectory on Uthong Nok road in Bangkok's Dusit district was damaged at 5am.
Seven fire engines took about 50 minutes to put out the flames.
Police are still investigating the cause of the fire.