Two Saudi-led airstrikes hit a market in Hajjah province, north-west of Yemeni capital Sana'a, on Tuesday killing at least 41 civilians and injuring more than 35, an official said.
"The number of casualties is expected to rise in the coming hours as rescue operations are under way," said Ayman Madkour, head of the local office of the Health Ministry in Hajjah.
He said most of the wounded had suffered severe injuries.
Hajjah province is on the border with Saudi Arabia.
The Saudi-led alliance has not yet commented on the incident.
Saudi Arabia and its allies, mainly Sunni Gulf countries, launched an air campaign in March 2015 against the mostly Shiite rebels who control large parts of Yemen.
Last month, up to 25 civilians were killed when an airstrike by the Saudi-led military coalition hit a market in the north of the impoverished country.
UN officials have called on the Saudis to halt their air campaign, saying that it is responsible for most civilian casualties in the conflict.
Yemen has been in turmoil since September 2014, when Iran-backed Houthis overran Sana'a and began making advances in the country.
Saudi Arabia fears that the rebels will give its regional rival Iran a foothold in the Arabian Peninsula.