They say Tuesday’s strike in the western province of Taiz wounded at least 30 others.
The witnesses and officials spoke on condition of anonymity because they feared retaliation or were not authorized to brief the media.
The coalition could not immediately be reached for comment.
International rights groups have accused the coalition of bombing civilian gatherings, markets, hospitals and residential areas across Yemen since the beginning of its air campaign against Iran-backed rebels, known as Houthis, in March 2015.
WATCH: At least 12 dead in Yemen after Saudi-led air strike
The stalemated war has killed more than 10,000 civilians and pushed the Arab world’s poorest country to the brink of famine.