Morgan Sindall has been selected to build the new home for St Hilda's Church of England High School in Sefton Park, Liverpool.
Morgan Sindall will build a new four-storey building on land in Sefton Grange, Croxteth Drive, next to the existing site. The present school building will then be demolished and used for games pitches, sports hall and car park.
It will be the sixth scheme to be delivered under the Liverpool Schools Investment Programme, in which Cllr Mayor Joe Anderson pledged to build 12 new schools for £169m.
Morgan Sindall expects to award 85% of the sub-contracts to firms in Merseyside, 68% in Liverpool.
As part of the scheme, the school will change from admitting only girls to a co-educational admissions policy when the new building opens on the site in September 2015. The sports facilities will be completed by February 2016. Subject to planning consent, construction work is expected to start in April 2014.