About 28.5 million children in conflict-plagued countries are being denied education.
The observation came from leaders from governments and international organisations at the UN General Assembly.
"We must make an intentional and deliberate turn from the past policy responses to humanitarian crises where education has typically been underfunded," said Gordon Brown, the United Nations'special envoy for global education. He was addressing a meeting of "Education Cannot Wait" on Monday.
"Today, with nearly one million Syrian refugee children, we have the opportunity to take immediate action and demonstrate that we can not only prioritise, but also deliver the promise of education for all."
More than half of the world's 57 million primary-school-age children, who are out of school, live in countries scarred by war and conflict, compared to 42% in 2008.
Conflicts, fighting and displacement in Syria, the Central African Republic, Mali, and the Democratic Republic of Congo, have largely contributed to this increase, according to Save the Children.
Education should never be the cost of conflict, Anthony Lake, executive director of the UN Children's Fund, said.
"Education cannot wait for battles to end...or disasters to be averted...or funding to be available. Education cannot wait...because children cannot wait," Lake said.
Alice Albright, chief executive officer of the Global Partnership for Education, said that education in emergency situations is severely underfunded, accounting for only 1.4% of humanitarian aid.
She proposed doubling the amount and improving coordination among governments, donors and humanitarian agencies.
"We all have a duty to the children of the world, to deliver good quality education regardless of the hostile conditions under which they live," said Tove Romsaas Wang, the chief executive officer of Save the Children Norway.