Prince William and Kate Middleton have kissed twice on the balcony of Buckingham Palace after their wedding service in Westminster Abbey.
They were cheered by 500,000 well-wishers who gathered outside the palace, as RAF planes flew past in honour of the new royal couple.
Police estimate a million people lined the procession route from the abbey to the palace.
The bride will now be known as the Duchess of Cambridge.
The Queen is hosting a buffet reception at the palace for 650 guests.
Following a long tradition, the ring has been fashioned from Welsh gold given to Prince William by the Queen.The church service, watched by 1,900 guests, ran smoothly but the prince did struggle to place the wedding ring on the duchess's finger.
After the couple said their vows, in which she did not promise to obey William, the Archbishop of Canterbury, the Most Reverend Rowan Williams, declared: "I pronounce that they be man and wife together, in the name of the Father, and of the Son, and of the Holy Ghost. Amen."
They spent a private moment together with their families, as they signed the marriage register.
Prince William has been given the title of the Duke of Cambridge by the Queen, and Miss Middleton has become Her Royal Highness the Duchess of Cambridge on their marriage.
The duchess, who managed to keep her wedding dress a secret, is wearing an ivory and lace gown by Sarah Burton at Alexander McQueen. The prince is wearing the red tunic of an Irish Guards colonel - his most senior honorary appointment.
Well-known faces spotted at Westminster Abbey included singer-songwriter Sir Elton John and his partner David Furnish, former England rugby coach Sir Clive Woodward, and former England football captain David Beckham and his wife Victoria.
Actor Rowan Atkinson, a close friend of Prince Charles, Prince Harry's friend Chelsy Davy and film director Guy Ritchie were also there.
UK Prime Minister David Cameron and his wife Samantha, Australian prime minister Julia Gillard, former British PM Sir John Major, and Home Secretary Theresa May were among the politicians present.
For those lining the route, large speakers broadcast the wedding service, and hundreds of millions of people were expected to watch the proceedings worldwide on television.
- According to a lip-reading expert, Prince William told his bride she looked "beautiful" as she joined him at the altar. Tina Lannin, of O'Malley Communications, also said he joked to his father-in-law Michael: "We're supposed to have just a small family affair"
- The fly-past involved Lancaster, Spitfire and Hurricane aircraft from the RAF Battle of Britain Memorial Flight
- The busy schedule began when guests start arriving at the Abbey from 0815 BST. Many had been queuing before the Great North Door opened
- A Rolls-Royce picked up Miss Middleton at the Goring Hotel, where the Middleton family were staying, at 1050 BST, and the ceremony got under way just after 1100 BST. Prince William travelled to the Abbey with his brother and best man in a Bentley
- Out of the 1,900 guests at the Abbey, 1,000 were friends and family, who had been given some of the best seats in the house. The others included overseas royals, politicians from home and abroad, military personnel and representatives from various faiths and charities
- After the service, the newly-weds travelled in an open-topped carriage for the 15-minute journey from Westminster Abbey to Buckingham Palace, past some of London's most famous landmarks, including the Houses of Parliament, Big Ben and Horse Guards Parade
- More than 1,000 military personnel and musicians lined the procession route
- Thousands of street parties are being held around the UK, and big screens have been put up in many towns and cities. The BBC has been bringing viewers and listeners comprehensive coverageacross TV, radio and online, both in the UK and around the world
- 5,000 officers were on duty, with more than 900 along the wedding route
- Police have made 43 arrests in and outside the security zone and questioned masked protesters in central London.
- About two square miles of central London have been closed to traffic.
Royal officials said the couple were involved in planning their wedding day, from the music at the ceremony to the flowers and the cake.
Inside Westminster Abbey, an avenue of trees lined the red carpet leading up to the altar.
The bride walked up the aisle to coronation anthem I Was Glad, by Sir Charles Hubert Hastings Parry, from Psalm 122. Her brother James Middleton gave the Lesson, reading Romans 12: 1-2, 9-18.
But the Queen and the Duke of Edinburgh will leave for a weekend away after hosting the lunchtime reception and will miss Prince Harry's best man speech and Michael Middleton's father of the bride address.
Despite predictions of showers, it stayed dry for the royal couple. Temperatures in London were expected to reach a high of 19C (66F) in the afternoon.