Kier will design and build a school for a site on the Wolsey Park development, off Rawreth Lane in Rayleigh. It will provide 150 places for pupils with special educational needs and/or disabilities (SEND).
The school will be run by Zenith Multi Academy Trust.
Chris Lilley, regional director at Kier Construction Eastern and Midlands, said: “We are excited to have the opportunity to work with Essex County Council and continue to grow our strong eight-year relationship with the council. With solid experience and expertise in education projects, our brilliant team are delighted to have the opportunity to serve the communities in which they live, deliver high-quality educational spaces and drive social value in Essex.”