The proposed new build will replace the existing Whitmore High School, which currently supports 905 pupils, with new facilities for 1,100 pupils.
The current school will remain open during construction and then be demolished.
Teaching space will be spread across three storeys, with 70 general classrooms and two drama and activity studios encompassed within the 11,000 sqm.
Sports facilities are provided indoors and out, including an all-weather pitch and a multi-use games court.
There will also be a music studio, an art centre, dining hall and multi-functional hall with retractable seating.
Work starts on the site in autumn 2019 and is expected to complete by spring 2022.
Vale of Glamorgan Council appointed Morgan Sindall through the South East and Mid Wales Collaborative Construction Framework (SEWSCAP), as part of Wales’ 21st Century Schools Programme. Morgan Sindall Construction was appointed to four lots on the new £1bn SEWSCAP framework earlier this summer. The four-year framework will be used by more than 20 Welsh councils and public bodies for schools, leisure facilities and municipal buildings.
Morgan Sindall Construction area director Rob Williams said: “This project represents a significant investment in the education offer for people in Barry and one we’re well placed to deliver. Morgan Sindall Construction is one of the most active school-builders across Wales. We have a track record of designing and building modern, inspirational teaching environments, fit for 21st century education and relish briefs like this.”