The deal worth around £10m includes 80 acres of land including Wynyard Park House, Evolution and the Business Village.
The purchase includes 100,000 sq ft of office space and around 1.6 million sq ft of industrial all currently let to around 60 individual tenants.
Occupiers include national as well as regional businesses such as Conoco Phillips, Wood Group, BP, Cleveland Police, Dunedin, Glamal Engineering, Nortec Oil and Gas, Gleeson Developments and Balfour Beatty.
Wynyard Park will retain ownership of the majority of the wider estate - 700 acres including office and industrial space accommodating Huntsman, Ensub and Barrier Architectural.
Development is also well underway on the construction of over 1,000 homes and supporting facilities to create a high quality mixed use development.
Colin Davidson, commercial property director at Northumberland Estates, said: “This is an exciting purchase for us and one which underlines a serious commitment to continued property investment in the region.
“The business park fits well with our existing portfolio of managed properties and the development land compliments our development pipeline.
“Through this we hope to further our construction plans in a way which is commensurate with market demand and so continue to bring jobs and new business both to Teeside and to the region."
In addition to the deal, Northumberland Estates and Wynyard Park have entered into a joint venture agreement on a further 100 acres of adjacent land zoned for development with a view to further investment at the site in the longer term.