Neath Port Talbot council has approved a planning application for the former Glan Afan Comprehensive School site.
The school closed its doors in July and pupils were transferred to the new "superschool" Ysgol Bae Baglan.
The plans, submitted by Coastal Housing Group, are part of a Â£35m regeneration programme for the town
The Victorian building's red brick facade will be maintained and will house a commercial unit along with 12 flats.
Other buildings to the rear of the site will be demolished to allow the construction of more flats, detached and semi-detached houses and another commercial unit.
Council leader Ali Thomas said the redevelopment would provide "much needed" housing for the town centre.
Plans to redevelop a former Port Talbot school site into flats have been given the go-ahead by councillors.