The Simonstown Agreement was a naval cooperation agreement between the United Kingdom and the (then-officially) Union of South Africa signed 30 June 1955. Under the agreement, the Royal Navy gave up its naval base at Simonstown, South Africa, and transferred command of the South African Navy to the government of South Africa. In return, South Africa promised the use of the Simonstown base to Royal Navy ships  The agreement also permitted South Africa to buy naval vessels from the UK valued at £18 million over the next eight years. In effect, the agreement was a mutual defence arrangement aimed at protecting sea routes between the UK and the Middle East. The agreement was controversial because of South Africa's policy of racial separation known as apartheid.
The government of the UK terminated the agreement on 16 June 1975. Ships of the Royal Navy continued to call periodically at Simon's Town and other South African ports, however the Royal Navy was not able to use any South African ports during the Falklands War.