The bus driver lost control of the vehicle before it fell about 30 metres into the ravine on a curvy rural road in Wang Nuea district in Lampang province yesterday, police Col. Somdet Tossaporn said. The driver was among 16 people injured.
The travellers had visited the temple to make merit, a Buddhist ritual of performing good deeds or other acts. Most of those killed were women.
Somdet said the driver is facing charges of causing deaths by reckless driving, which carry a maximum jail term of 10 years.
Up to 26,000 people are killed in road accidents every year in Thailand, according to the Interior Ministry.