The victims were returning from a religious ceremony when the vehicle left the road, Police Colonel Somdet Tosporn told AFP by telephone from Lampang province.
"The bus fell into a ravine about 10 metres deep," he said. "I can't confirm the cause but the road is curvy."
No foreigners were believed to be on board.
Deadly road accidents are common in Thailand.
A recent report by the World Health Organisation said the country saw some 38.1 road deaths per 100,000 of population, compared to an average of 18.5 in Southeast Asia as a whole.
In July at least 19 people were killed when a double-decker coach collided with a truck in central Thailand and burst into flames.
In April at least five people were killed, including a seven-month-old baby, and 53 were injured when a Thai tour bus plummeted off a hillside in the northern province of Phitsanulok after its brakes failed.
You’ve reached your limit of {{free_limit}} free articles this month.
Subscribe now for unlimited access.
Already subscribed? Log in
Subscribe to read the full story →
Smart Quarterly
₹900
3 Months
₹300/Month
Smart Essential
₹2,700
1 Year
₹225/Month
Super Saver
₹3,900
2 Years
₹162/Month
Renews automatically, cancel anytime
Here’s what’s included in our digital subscription plans
Exclusive premium stories online
Over 30 premium stories daily, handpicked by our editors


Complimentary Access to The New York Times
News, Games, Cooking, Audio, Wirecutter & The Athletic
Business Standard Epaper
Digital replica of our daily newspaper — with options to read, save, and share


Curated Newsletters
Insights on markets, finance, politics, tech, and more delivered to your inbox
Market Analysis & Investment Insights
In-depth market analysis & insights with access to The Smart Investor


Archives
Repository of articles and publications dating back to 1997
Ad-free Reading
Uninterrupted reading experience with no advertisements


Seamless Access Across All Devices
Access Business Standard across devices — mobile, tablet, or PC, via web or app
