Admiral of the Fleet John Jervis, 1st Earl of St Vincent was an admiral in the Royal Navy and Member of Parliament in the United Kingdom. Jervis served throughout the latter half of the 18th century and into the 19th, and was an active commander during the Seven Years' War, American War of Independence, French Revolutionary War and the Napoleonic Wars. He is best known for his victory at the 1797 Battle of Cape Saint Vincent, from which he earned his titles, and as a patron of Horatio Nelson.

Admiral of the Fleet is a five-star naval officer rank and the highest rank of the Royal Navy, formally established in 1688. The five-star NATO rank code is OF-10, equivalent to a field marshal in the British Army or a Marshal of the Royal Air Force. Apart from honorary appointments, no new admirals of the fleet have been named since 1995, and no honorary appointments have been made since 2014.