A new £4.65 million classroom block is being built at Princethorpe College.
The Princethorpe Foundation investment forms part of a £10 million ten-year capital expenditure programme.
A £3.5million funding package from HSBC has also been secured to support the project.
The development includes 14 new classrooms for English and modern foreign languages, including two new IT suites.
Development is under way and work is due to be complete by the start of the 2014/15 academic year.
Princethorpe College is an independent school, with more than 850 pupils enrolled.
The nursery and junior school has 220 pupils.
The school is also upgrading some of its existing facilities and will develop a state-of-the-art technology centre, additional sports pitches, a new theatre and more science laboratories over the ten year programme.
Foundation bursar Eddie Tolcher said: “This programme is aimed at improving the facilities at the school for existing pupils.
“The school has reached its optimum size and we want to ensure our pupils learn and development in the best environment possible.
“We are very excited about the new classroom block and the future developments in the pipeline.”