The Forest Moor complex in Nidderdale will be remodelled and refurbished by ISG Regions to provide a 40-bed school for pupils aged 11 to 16.
It was originally built in the 1980s. The eight-hectare site currently includes two residential blocks, a dining and social area, offices and classrooms, a sports hall, a car park and a football pitch.
North Yorkshire County Council plans to open the school in September to replace Baliol School in Sedburgh, Cumbria.
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