Sodexo has been awarded a seven-year catering and cleaning contract at Holyport College in Berkshire worth £2.6m.
Services will commence when the co-educational day and boarding school for students aged 11 to 19 years old opens in September 2014.
Sodexo will initially cater for around 120 pupils on-site which will rise to 500 within five years, with 45% set to be boarding students.
James Bell, the bursar for Holyport College, said: "We have every confidence that our pupils will be receiving nutritional, high quality food to help prepare them for learning every day. Together with our own staff and other partners, Holyport College is looking forward to working with Sodexo to create a clean, healthy and vibrant learning environment."
Jeremy Alderton, managing director of Sodexo Independent Education, added: "Holyport College will be our first state boarding school which gives us a great opportunity in this growing market. Our resources and extensive client list in Berkshire helped us win this prestigious free school which has Eton College as its sole educational sponsor.
"The local Sodexo teams including our team at Eton College will help support the success of the brand new school that opens its doors for the first time in September."