An official school population forecast says pupil numbers will rise by a further 10% in the next decade.
The pressure on creating new schools and extra classrooms will be one of the challenges for incoming Education Secretary Justine Greening.
Schools will have faced 16 consecutive years of rising pupil numbers.
The Department for Education says it has committed £7bn to extra places.
Between 2009 and 2016, the school system had already expanded to take in an extra 470,000 pupils.
Read more about this story on the BBC website: Extra 750,000 school places needed in population surge | BBC News