The green light has been given by education officials for the expansion of Polegate School.
It means that from September 2019 an extra 60 pupils will be able to be admitted and eventually the roll call will rise from 420 to 630 pupils.
Building work will also be carried out.
The expansion plan was rubber stamped at a member of East Sussex County Council’s education committee on Monday at County Hall in Lewes.
An education spokesperson said, “In recent years demand for school places in Polegate has increased as a result of new housing developments in the area.
“Latest birth and GP registration data indicates that in-area demand for places will continue to exceed the number of places available at the school in the coming years.
“Polegate school is a popular and successful school and has for the last two years admitted bulge reception intakes to provide more places. For the September 2017 intake, 96 parents and carers selected the school as a first preference.
“The school’s current Published Admission Number of 60 provides limited scope to meet parental preference.”
The spokesperson said the council as the education authority had a statutory duty to ensure there are sufficient school places to meet demand.
“The expansion of Polegate School will create additional capacity to serve the new housing developments in the area,” said the spokesperson.
“The majority of respondents to the consultation support the proposal to expand. “Concerns raised relate largely to traffic and parking, loss of playing field and facilities and the requirement to enlarge the school hall. “These issues will be addressed through the detailed design process undertaken as part of the planning permission process.”