Holy Cross Sixth Form College in Bury has acquired half of one acre next to the school from the Abbeyfield Society for £700,000.
The land formerly contained sheltered accommodation and will allow the college to expand in the future.
Mike Redshaw, director of Nolan Redshaw, advised the college. He said: "We have been working closely with the college and Abbeyfield Society for the last three years to agree this deal. Negotiations on this project were, at times, difficult and sensitive but we are delighted to have been able to reach a mutual decision that enables Abbeyfield Society to reinvest in their existing portfolio and for Holy Cross College to acquire additional land, which will be vital for the future growth of the college."