The Girls Education Challenge will involve non-governmental organisations (NGOs), charities and the private sector, and will only get batches of funding if they can prove their schemes are working.
It aims to help 650,000 girls with a full six years of primary education or up to one million girls with a junior secondary education for three years.
"Women and girls continue to bear the brunt of poverty,” said Deputy Prime Minister Nick Clegg as he rolled out the scheme last night (Monday.)
“Investing in them early on and giving them an education not only radically alters their lives but has a massive knock-on effect benefiting their families and communities. Girls who have been to school are likely to do significantly better financially, socially and be far healthier," he said.
"The action we are taking is ambitious and something of which Britain should be enormously proud. It will help to lift hundreds of thousands of girls out of poverty so that they can fulfil their potential."
Businesses and aid organisations that get involved will have to show "measurable improvements" in the quality of girls' education and higher numbers of them going to school.
Girls who go to school are more likely to marry later, have fewer children, get jabs for themselves and their babies, avoid HIV and find work, said the Department for International Development, fleshing out the details of the scheme.
“Educating girls tackles the root causes of poverty. Research shows that providing girls with an extra year of schooling can increase their wages by up to 20 per cent, while also lowering birth rates, which can have a profound economic impact,” said the department’s Andrew Mitchell who is expected to speak more about the scheme at the UN General Assembly this week.
“These initiatives will also have positive impacts on future generations. They will mean girls are more likely to go on to help their sisters and younger girls in the community to follow their example – go to school and widen their choices, to get married later, for example, and to earn their own income.”