Redrow purchased the 34.4 acre site in Wilton by formal tender and plans to re-develop the land as part of a community partnership with OurEnterprise and the Wilton Community Land Trust.
The site has already been granted outline planning permission for the creation of dwellings and employment accommodation.
Erskine Barracks was occupied by the MoD up until 2011 when it was considered surplus to requirements.
Redrow group managing director John Tutte said: "We are delighted to have acquired the Erskine Barracks site from DIO and we look forward to working with our local partners, OurEnterprise and the Wilton Community Land Trust, to deliver a development that will provide much-needed sustainable new homes, accommodation for veterans, and permanent jobs for the local economy".
The MoD has also sold three sites in Bath to local housing developers and the RAF Bicester site. The Bath sites are at Foxhill, Warminster Road and Ensleigh.
The Foxhill site has been purchased by Curo, one of the largest social landlords in the West of England.
Warminster Road has been purchased by a joint venture between developers Square Bay and Firmstone Developments.
Ensleigh has been bought by a subsidiary of IM Properties, which plans to remediate and redevelop the site for approximately 250 new homes.
The RAF Bicester site, redundant since 2004, has been bought by Bicester Heritage Limited, which plans to establish a “heritage-oriented commercial park”.