The Ministry of Defence Main Building or MOD Main Building, also known as MOD Whitehall or originally as the Whitehall Gardens Building, is a grade I listed government office building located on Whitehall in London. The building was designed by E. Vincent Harris in 1915 and constructed between 1939 and 1959 on part of the site of the Palace of Whitehall, specifically Pelham House, Cromwell House, Montagu House, Pembroke House and part of Whitehall Gardens. It was initially occupied by the Air Ministry and the Board of Trade before becoming the current home of the Ministry of Defence in 1964.
By the 1990s the building was no longer considered fit for purpose and had become expensive to maintain. A major refurbishment was therefore undertaken between 2000 and 2004 through a private finance initiative contract.