The companies will serve as suppliers for the principal support provider (PSP) framework, which has been developed by the DIO on behalf of the UK Ministry of Defence and the Foreign and Commonwealth Office.
With an estimated spend value of £60m, the framework demonstrates a commitment across government departments to work together on overseas procurement.
The selected suppliers, including AECOM , Atkins, Mott MacDonald , Ramboll, Ridge & Partners and WYG, will deliver multi-disciplinary design, project management and advisory services, as well as specialist surveys and clerk duties.
Defence Infrastructure Organisation International Projects deputy head David Graham said: “We are pleased to welcome these suppliers on board following a successful procurement process.
"We look forward to working with them, the Foreign Office and other areas of government to lead on projects that support our military personnel who live, train and work overseas.
“As the key government departments which manage overseas projects, it’s essential that we continue to work together to ensure a consistent approach to procurement of project management and other support for our overseas estate.”
The six firms participate in mini-competitions within the framework, after which a suitable contractor will be selected to deliver a project.
The contractor will then deliver services overseas for the next four years.