The attack hit a civilian house in al-Rawdhah neighborhood in the province's namesake capital city Marib.
The victims were a woman and a child while six others, mostly children, were wounded in the attack which destroyed the house.
The Houthi group has not claimed responsibility for the attack.
It was the second attack in fewer than a week after a Saturday's suspected Houthi missile attack on an adjacent military training camp that killed more than 100 soldiers and injured dozens of others, according to the government officials.
Marib, about 170 km east of the Houthi-held capital Sanaa, is controlled by the government forces of Yemeni President Abd-Rabbu Mansour Hadi, which have been battling Houthi rebels for nearly five years.
Earlier in the day, the Saudi-led coalition in support of the Yemeni government launched airstrikes on Houthi rebels who are fighting against government forces in Nehm district, some 60 km northeast of Sanaa, a Yemeni government official in Marib told Xinhua on condition of anonymity.
The clashes in Nehm, which links Marib with Sanaa, have lasted four days, killing scores from both sides as the government forces are pushing toward Sanaa, according to pro-government news website al-Masdar Online.
Yemen has been mired in a civil war since late 2014, when the Iran-backed Houthi rebels seized control of much of the country's north and forced the Saudi-backed government of Hadi out of Sanaa.