A 13-classroom block and £4m canteen is the latest part of a £12m expansion plan for a Wantage secondary school.
The new three-storey building would also be a community centre for evening classes, King Alfred’s Academy has said.
The academy is also planning to build a new £3m science block and a £4m sixth-form block in the coming years.
Headteacher Simon Spiers said the school was preparing for a population increase from 5,000 new homes in Wantage and Grove.
He said: “This is a significant step forward for the academy, replacing a dilapidated, single-storey building with a stunning new restaurant and two floors of superb classrooms.”
Mr Spiers said the maths and English classrooms would allow the school to accommodate pupils while knocking down and rebuilding across the centre site on Portway.
The school has recently finished work on a £720,000 new art and design block with a new assembly hall.
Mr Spiers said that would have a grand opening on April 25 with a “very special” guest.
He said that none of the expansion plans would have been possible if the school was not an academy, which allowed it to bid for funding from the Educational Funding Agency (EFA).
The school has put in a bid to the EFA for £3.85m towards the new English and maths block, and will contribute £350,000 itself.
Wantage and Grove are due to expand by about 5,000 homes including the new Grove Airfield and Crab Hill estates, granted permission in the last few months.
Mr Spiers said the academy, which currently has 1,800 students, will be full by 2017.
He said the school would look to increase its capacity by building new blocks closer to the time, depending on the need forecast by the education authority, Oxfordshire County Council.
The school has applied for planning permission for the new block to Vale of White Horse District Council, which is due to decide by June 5.