The wedding of Prince Charles and Lady Diana Spencer took place on Wednesday, 29 July 1981, at St Paul's Cathedral in London, United Kingdom. The groom was the heir apparent to the British and Commonwealth thrones, and the bride was a member of the Spencer family.

The ceremony was a traditional Church of England wedding service. Alan Webster, Dean of St Paul's, presided at the service, and Robert Runcie, Archbishop of Canterbury, conducted the marriage. Notable figures in attendance included many members of other royal families, republican heads of state, and members of the bride's and groom's families. After the ceremony, the couple made the traditional appearance on the balcony of Buckingham Palace. The United Kingdom had a national holiday on that day to mark the wedding. The ceremony featured many ceremonial aspects, including use of the state carriages and roles for the Foot Guards and Household Cavalry.

Their marriage was widely billed as a "fairytale wedding" and the "wedding of the century". It was watched by an estimated global television audience of 750 million people. Events were held around the Commonwealth to mark the wedding. Many street parties were held throughout the United Kingdom to celebrate the occasion. The couple separated in 1992 and divorced in 1996 after fifteen years of marriage.