Steeped in history, it offers Prince Harry and Meghan Markle a slightly more intimate venue for their nuptials, but one that is still appropriately grand for a royal wedding.
It usually holds around 800 guests compared with the 2,000 capacity of Westminster Abbey where the Duke and Duchess of Cambridge wed in 2011.
With the Queen now 91 and the Duke of Edinburgh 96, the choice will be especially convenient for Harry’s ageing grandparents, who spend a great deal of time at home in the castle.
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Located within the castle’s grounds and surrounded by the Horseshoe Cloisters and the Henry VIII gate, the venue will also provide the royal family with a certain amount of privacy on the day of the wedding.
Harry was also christened in the chapel in December 1984 when he was three months old, which, according to Church of England rules, means he can also marry there.
The prince and Ms Markle’s reception could be held in the castle’s 180ft (55m) long St George’s Hall, traditionally used for glittering state banquets.
The vast hall had to be restored following the devastating fire at the castle in 1992.
The chapel, with its intricately carved stonework, magnificent fan vaulted ceiling and beautiful stained glass windows, has seen many royal weddings and funerals.
The last royal wedding was for Harry’s cousin, Peter Phillips - son of the Princess Royal - who married Canadian Autumn Kelly in 2008.
Harry’s father, the Prince of Wales, and stepmother, the Duchess of Cornwall, had their televised religious blessing there in 2005, after their civil ceremony down the road in Windsor’s Town Hall.
In 1999, Harry’s uncle, the Earl of Wessex, married Sophie Rhys-Jones, now the Countess of Wessex, at St George’s.
Royal newlyweds and their families traditionally pose for photographs afterwards on the vast west steps, as Harry and his new bride are certain to do.
It has been the setting for many historic funerals including the Queen Mother’s private committal service following her Westminster Abbey funeral in 2002, and in the same year, Princess Margaret’s small, private funeral.
The funeral of the Queen’s father, King George VI, took place at St George’s in 1952.
Like Westminster Abbey, the chapel is known as a Royal Peculiar, with the Dean of Windsor responsible only to the sovereign.
The church - a place of worship for the Queen and her family - is often at the heart of royal events, with the Windsors gathering there each year for Easter services, and in the past for occasions such as the service to mark the Duke of Edinburgh’s 90th birthday.
Within the chapel are the tombs of 10 sovereigns - as well as George VI, the remains of Edward IV, Henry VI, Henry VIII and his third wife Jane Seymour, the beheaded Charles I, George III, George IV, William IV, Edward VII and George V also rest there.
Construction of the chapel was started in 1475 by Edward IV, and completed under Henry VIII in 1528.
It is the Chapel of the Order of the Garter, the senior order of chivalry in England, established in 1348 by Edward III.
Each year in June, royals who are Knights and Ladies of the Garter process in carriages from the state apartments down the hill to the chapel for the traditional Order of the Garter ceremony.
They dress in their Garter robes - heavy blue velvet capes and black velvet hats with elaborate white ostrich plumes.
On each side of the choir are the 15th century beautifully carved stalls of the Knights and Ladies of the Garter.