A number of people at the Ban Mae Surin camp were injured in the blaze, which destroyed about 100 makeshift houses.
Officials say the fire may have been started by a cooking accident, but an investigation is still under way.
More than 3,000 refugees from Burma – mostly from the Karen minority – live at the camp. Those who lost their homes are being temporarily housed in tents.
The fire started at about 16:00 local time (09:00 GMT) in the camp in Mae Hong Son province, the local officials say.
“Most of the dead are women, elderly and children. Some 200 are wounded,” one official was quoted as saying by the AFP news agency.
The blaze was extinguished about two hours later.
It is estimated about 130,000 Burmese refugees have fled conflicts in the country and are currently living in camps in northern Thailand.