HMS Sirius (F40) was a Leander-class frigate of the Royal Navy (RN) built by H.M. Dockyard Portsmouth, and was the penultimate RN warship to be built there for a period of forty years, until Vosper Thornycroft built HMS Clyde. Sirius was launched on 22 September 1964 and commissioned on 15 June 1966. The ship continued in front line service until February 1992.