The Royal Yacht Squadron is one of the most prestigious yacht clubs in the world. Its clubhouse is Cowes Castle on the Isle of Wight in the United Kingdom. Member yachts are given the Suffix RYS to their names, and permitted to fly the White Ensign of the Royal Navy[1] rather than the merchant Red Ensign flown by the majority of other UK registered vessels. The club's patron is Queen Elizabeth II and the club’s admiral is Prince Philip who is also a former club commodore.

Founded on 1 June 1815 in the Thatched House Tavern in St James’s, London as The Yacht Club by 42 gentlemen interested in sea yachting.[2] The original members decided to meet in London and in Cowes twice a year, to discuss yachting over dinner. Membership was restricted to those who owned a vessel not under 10 tons. Today this is interpreted as a gentleman “actively interested in yachting”.[1]

The Earl of Yarborough, later first commodore of the club, welcomed the Prince Regent as a member in 1817. In 1820, when the Prince Regent became George IV, it was renamed the Royal Yacht Club.

The club started organising racing as a principal feature of the annual regatta, which is now known as Cowes Week. In 1833 William IV renamed the club, The Royal Yacht Squadron. Its association with the Royal Navy began early and Nelson's captain at Trafalgar, Admiral Sir Thomas Hardy, headed the list of naval members. The spirit of invention led to yachts “of such celerity in sailing and beauty of construction” that they were of utility to the Royal Navy. In 1829 the Admiralty issued a warrant to wear what is now the navy’s White Ensign. The burgee (a triangular shaped flag identifying yacht club membership) is differenced with a St George's Cross and crown on a white background.

Another naval connection is that the Antarctic explorer Captain Scott was a member of the Royal Yacht Squadron. To enable the application of naval discipline on board a civilian ship, he registered the Terra Nova R.Y.S. as a yacht of the squadron and sailed under the White Ensign on his second and final expedition to Antarctica in 1910. Racing Genesta (1885), the club's first challenger for the America's Cup

In 1851, the club's commodore, visiting the Great Exhibition, issued a challenge for the squadron’s £100 Cup for a race around the island. The New York based ‘’America’’, representing the New York Yacht Club triumphed in this race giving its name to one of the oldest and best known trophies The America's Cup. The victory was witnessed by Queen Victoria and the Prince of Wales, later commodore of the club and Edward VII.

The site is also used as the start of the Round the Island Race which occurs annually.

During the American Civil War Deerhound RYS witnessed the fight between USS Kearsarge and the Confederate cruiser CSS Alabama. Gazelle RYS rescued the Empress Eugenie at the end of the Franco-Prussian War and the squadron yachts supplied British soldiers in the Crimean War.