"The world is facing a girls' education crisis," with more than 130 million girls missing out on school around the world, Malala Yousafzai has warned.
She said the recovery from the pandemic had to mean fair access to education.
The Global Partnership for Education summit wants to raise $5bn (£3.6bn) to support education in some of the world's poorest countries.
Hosted by the UK and Kenya, it will raise funds for the next five years, creating an extra 88 million school places and supporting the learning of 175 million children.
The pandemic has exacerbated the problems already facing schools in poorer countries - with warnings that children who were forced out of school because of coronavirus might never return.
She said the pandemic had disrupted education in all countries - but the impact of closing schools had been much worse in poorer countries where many families lacked access at home to internet connections or electricity.