The nearly 9,000 square foot buildings will include 250 sixth form pupils and will be built on the old Smurfit Kappa Lokfast site along London Road.
The new academic building will include a 4-storey tall teaching block and a 2-storey sports hall, and will provide around 120 full-time jobs.
Chair of Planning, Cllr Tom Kelly said: "There is a lot of regeneration taking place across the borough. What is nice about this particular project is that we're seeing the facilities being built before the houses â?? which is encouraging.
"Harris is an excellent school group and the local authority has worked extremely well with its existing schools in Chafford Hundred â?? I see no reason why this will be different."
Cllr Kelly added: "I think this school is much needed, and Iâ??m pleased the committee was able to support the application."
For more information on regeneration projects taking place across the borough, go to thurrock.gov.uk/growth