More than 250 million children around the world don't go to school, according to UNICEF.
More than 250 million children around the world don't go to school, according to Unicef, and one quarter of the world's school-age children live in areas threatened by war.
After six years of war in Syria, almost a million Syrian children refugees live in Lebanon and Jordan and more than half of them are still not receiving any education, said Kevin Watkins, chief executive of Save the Children UK.
"You will wipe out a whole primary school generation, before the international community even moves on education," he told a conference in The Hague.
"I think what we need is universal plans of action for all refugee children... no refugee child should be out of school more than a term or two terms," he added at the Hague Institute for Global Justice.
International advocate for children's rights, Graca Machal, the widow of Nelson Mandela, said: "It's time perhaps we rethink how we address what we call humanitarian settings."
"We have been focusing on providing food, health, water," she said, adding that "only two percent of humanitarian funds go to education" and urging the UN Security Council to look at the issue.
There was also a focus on South Sudan where a civil war has left tens of thousands dead since 2013 and displaced some 3.5 million people.
More than half of South Sudan's primary school kids, and those in the first classes of secondary school, are no longer receiving any schooling.
"We need to look at the lack of education as an emergency situation," said American actor Forest Whitaker, UNESCO special envoy for peace and founder of the Whitaker Peace and Development initiative.
Founder of the Education Above All (EAA) campaign, Sheikha Moza bint Nasser al-Misnad, mother of the Qatari emir Sheikh Tamim bin Hamad Al-Thani, said there was "an unprecedented crisis" with education being used as "an instrument of war".
"Education is the cornerstone of sustainable development," she added. "We cannot construct a building if the cornerstones keep getting destroyed. Nor can we construct a durable building without investing in education as a tool in post-conflict recovery".
Chief prosecutor at the International Criminal Court Fatou Bensouda highlighted how often in war zones schools are turned into training bases for militias, children are kidnapped to be indoctrinated as child soldiers, spies and sex slaves.
Despite the horrors they endure, children still often retain an irrepressible optimism.
"They still believe they are going to be doctor or an engineer," said Watkins, adding "we need to keep that hope alive".