Admiral of the Fleet Sir Fairfax Moresby, GCB (29 November 1786 – 21 January 1877) was a Royal Navy officer. As a junior officer he took part in the unsuccessful Ferrol Expedition during the French Revolutionary Wars. He later saw action during the blockade of Brest during the Napoleonic Wars before becoming commanding officer of a sloop which was sent to the Aegean Sea to defend the population of Malta from pirates; the grateful people presented him with a sword.
Moresby then sailed to the Adriatic Sea where he led a naval brigade providing artillery support to the Austrian forces during the siege of Trieste. He went on to be senior naval officer at the Cape of Good Hope and then senior officer at Mauritius, with orders to suppress the slave trade: he concluded the Moresby Treaty with Said bin Sultan, Sultan of Muscat and Oman, restricting the scope of local slave trading and conferring on British warships the right of searching and seizing local vessels.