Some £350,000 of funding will be invested into the kitchen at North Kesteven School near Lincoln to extend capacity and completely refurbish the restaurant.
Staff say that due to the extra demand for primary school meals from September 2014, the facilities need to be expanded to cope with the uptake.
Work started on July 21 and is expected to be completed by September 2014.
The kitchen at the school on Moor Lane, North Hykeham, currently makes and delivers over 400 healthy and varied meals every day to a number of local primary schools.
From September, the school will be supplying an additional 360 meals to local primary schools – a total of 700.
The sum, from the Capital Maintenance Fund, has enabled the school to work with other local companies to start with the expansion plans.
Richard Mellows, Deputy Headteacher at North Kesteven School, said: “We are proud of our good relationships with the local primary schools and our catering team work tremendously hard to supply them with freshly cooked, nutritious meals.
“The extension and refurbishment taking place will allow our staff to serve even more meals as well as allowing large numbers of students and staff to relax and enjoy eating in a state of the art restaurant.”