This week marked 1,000 days since the escalation of a conflict which has uprooted more than 2 million people, left 8.4 million close to famine and triggered a massive cholera epidemic. The warring parties have attacked schools and hospitals and restricted aid.
Although Yemen has made some headlines this year, agencies said the coverage did not begin to reflect the enormity of what was happening.
"The lack of public awareness ... is truly shocking given the sheer scale of suffering and deliberate starvation of much of the population," said Jean-Michel Grand, executive director of Action Against Hunger UK.
"The past year has been incredibly harrowing," said Islamic Relief Worldwide CEO Naser Haghamed. "Despite an increase in media coverage and political intervention, the true scale of the emergency is still not dominant in the consciousness of the wider world."
International Medical Corps said the level of need was "unfathomably immense" and the situation almost entirely man-made.
According to a survey of aid agencies, Yemen was named the most neglected emergency by Action Against Hunger, Islamic Relief, International Medical Corps, Danish Refugee Council. Other agencies named:
Democratic Rep. of Congo - WFP, Christian Aid, Norwegian Refugee Council, CARE, Save the Children, FAO, World Vision, UNICEF
Central African Republic -UNHCR, Oxfam, International Rescue Committee