The Royal Fleet Auxiliary (RFA) is a civilian-manned fleet owned by the British Ministry of Defence. The RFA enables ships of the United Kingdom Royal Navy to maintain operations around the world. Its primary role is to supply the Royal Navy with fuel, ammunition and supplies, normally by replenishment at sea (RAS). It also transports Army and Royal Marine personnel, as well as supporting training exercises.

The RFA counts a forward repair ship and landing vessels amongst its assets. RFA personnel are members of the Ministry of Defence civil service who wear Merchant Navy-style rank insignia with naval uniforms and are under naval discipline when the vessel is engaged on warlike operations. RFA vessels are commanded and crewed by these civilians, augmented with regular and reserve Royal Navy personnel to perform specialised military functions such as operating and maintaining helicopters or providing hospital facilities. The RFA is funded out of the UK defence budget and the Commodore commanding the RFA is directly responsible to the Royal Navy Commander-in-Chief Fleet (CINCFLEET).