Children's charity Unicef has urged policymakers at the World Economic Forum to address the education spending gap, after it found 30% of the world's poorest teenage girls have never been to school.
The United Nations charity analyzed data from 42 countries, looking at children aged 10-19, in a report launched at the Education World Forum in London this week.
It found fewer (20%) of the world's poorest boys had never attended school. However, it reported that an equal number of boys and girls (14%) had dropped out of education in primary school, the British equivalent of elementary school.
The report said children from the world's poorest households already faced obstacles to education as basic as gender discrimination and physical distance from their school.
But it went on to blame "major disparities in the distribution of public education spending" as a barrier to learning, as this resulted in large class sizes, poorly trained teachers, lack of education materials and poor school infrastructure.
Unicef found that children from the richest 20% of households received around double the amount of education funding than the poorest 20%.
This disparity was the most pronounced in Africa, for instance in Guinea, where the richest children benefited from nine times the education funding allocated to the most deprived young people.
Nordic countries Denmark, Norway and Sweden, along with Ireland and Barbados were the only countries included in the report found to have an equal distribution of funding between the richest and poorest households.
Unicef also cited data from the World Bank, saying more than half of children living in low- and middle-income countries could not read or understand a simple story by the end of primary school.
The charity recommended allocating at least 10% of national education budgets to universal pre-primary education as one way for governments to address this problem, saying this was the foundation for any level of schooling.
Henrietta Fore, executive director at Unicef, said countries were failing the world's poorest children and therefore "failing themselves," adding that as long as funding remained disproportionate, they would have "little hope of escaping poverty."
She said countries were at a "critical juncture" but that investing equally in children's education would offer the best chance of lifting them out of poverty "by empowering them with the skills they need to access opportunities."