Steyning Grammar School is taking over the site of The Towers after the historic convent school announced it will be forced to close.
A spokesman for Steyning Grammar School said the school had agreed a lease of the site from September 1, 2020, with a projected opening date planned for 12 months later.
On Thursday (January 16), The Towers Convent School announced it would be closing at the end of the summer term after 117 years serving Upper Beeding and the surrounding area.
A decline in pupil numbers and an uncertain economic climate were given as reasons for the closure.
Later that same day, Steyning Grammar School revealed it would be selling its Church Street site in Steyning - which first opened its doors as a school 400 years ago - and would be moving its sixth form to a new site.
With the Church Street site considered 'no longer fit for purpose', the move would progress the grammar school's plans to join the Bohunt Education Trust (BET), a multi-academy trust which runs seven schools plus a sixth form.
It has now been revealed the grammar school's sixth form will be moved to The Towers site in Henfield Road, Upper Beeding.
The spokesman for Steyning Grammar School said: "Steyning Grammar School is hoping to move its sixth form provision to The Towers site with a projected opening date of September 2021. Steyning Grammar School have now agreed to take a lease of the site effective from September 1, 2020.
"In the meantime Steyning Grammar School will provide all support it can for the Sisters, the staff and children of The Towers during their closure period. The Sisters will remain on the site and work with us at Steyning to assist in the continual drive to improve young people’s educational outcomes and life chances."