The Erawan Emergency Medical Centre, operated by Bangkok city authorities, said that Apinya Sukthongsa, 20, died in hospital early on Sunday.
Around 70 people were injured in the fire and 13 were still in intensive care units, the Erawan centre said.
Thailand’s approach to health and safety regulations – particularly in bars and nightclubs – has long raised concerns.
In 2009, a blaze tore through Bangkok’s Santika club during New Year celebrations, killing 67 people and injuring more than 200.