Gwydyr House (Welsh: Tŷ Gwydyr) is a Grade I listed mansion in Whitehall, and is the London headquarters of the Wales Office. The house lies on the eastern side of the street, opposite Dover House.
Gwydyr House was built for Peter Burrell of Beckenham, Kent, in 1772 at an estimated cost of £6,000. The house is named after his son, also called Peter Burrell, who was created 1st Baron Gwydyr in 1769. It remained privately owned until 1835 when the house became unoccupied. Between 1838 and 1840 the premises served as temporary accommodation for the Reform Club. Since 1871 Gwydyr House has been used for official purposes.
Amongst the earliest official occupants of Gwydyr House were the Commission of Fine Arts, the Commission of Revenue Inquiry and the Commission of Slave Compensation. The Secretary of State for Wales, Peter Hain, unveiled a plaque in Gwydyr House in March 2007 to mark the bicentenary of the Abolition of the Slave Trade Act of 1807. Later in the nineteenth century, Gwydyr House was occupied by the Board of Health, the Poor Law Board and the Charity Commission. Since 1971, the premises have been occupied by the Welsh Office, now the Wales Office.