The Pestalozzi International Village site has been sold.
The Observer reported in September that the charity had put the 138 acre site on the market as it began to wind down its 60-year-old operation in Sedlescombe.
The site, in Ladybird Lane, includes 36,500 sq ft of existing buildings, including student accommodation and conference rooms.
Pestalozzi supports high achieving, but low income, students from some of the most disadvantaged communities in the world, providing scholarships to enable them to complete high quality secondary education. The students use their new skills to make their home countries a better place.
The charity announced this summer that the current students will be the last to stay at the village.
A lack of funding was blamed for the decision to sell the site.
The identity of the buyer has not been revealed and it is not yet known how much the site has been sold for.
Pestalozzi and estate agent Batcheller Monkhouse declined to comment on the sale.