Two years of war in the gulf state has brought seven million people to the brink of starvation.
CAFOD and Tearfund are among charities supporting the Disasters Emergency Committee's Yemen Crisis appeal.
Money raised at churches and mosques will be used to provide millions of people with food, medical supplies and shelter.
Tearfund has asked congregations to donate Advent collections to the appeal and called on Christians to pray for the country.
Rev Virginia Luckett, Director of UK Churches at Tearfund, said: "Yemen is facing one of the worst humanitarian crises of our time, and we're encouraging Christians and their churches across the UK to come together to support the appeal, both by prayer and giving.
"We heard just today that St Mary's Church in Welwyn held their 'Big Carol Sing' for the Yemen Crisis Appeal, collecting more than £250. This is typical of our generous supporters, who are digging deep at this busy time of year. We welcome any support that people can offer."
Tearfund is working through a local partner to provide hygiene and sanitation packs to prevent the spread of cholera plans to train first aid responders in areas where medical facilities have been destroyed.
Catholic parishes will also be holding collections for the DEC Yemen Crisis Appeal as part of their Christmas services this weekend.
Jo Kitterick, Head of Parish and Volunteer Engagement at CAFOD, said: "Advent is a time of prayer and reflection, and we ask that the people of Yemen are kept in thoughts and prayers over the coming weeks."
The DEC Yemen Crisis Appeal has raised more than £8 million so far.