Prince William and Kate Middleton have been pronounced man and wife at Westminster Abbey.
Some 1,900 guests watched the couple exchange their vows, with many millions watching at home.
They left the Abbey, with Kate Middleton now the Duchess of Cambridge, amid cheers from thousands of well-wishers lining the procession route.
They are now at Buckingham Palace where the Queen is hosting a buffet reception for 650 guests.
The couple travelled in an open-topped 1902 State Landau carriage for the procession, which was used by Prince William's parents for their wedding in 1981.
The couple are due to appear on the balcony at about 1325 BST.
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.
The church service ran smoothly but the prince did struggle to place the wedding ring on the duchess's finger.
Following a long tradition, the ring has been fashioned from Welsh gold given to Prince William by the Queen.
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.
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.
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.
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 current Home Secretary Theresa May were among the politicians present. Mr Cameron did not cause an etiquette upset and wore a morning suit despite initially suggesting he might not.
For those lining the route, large speakers broadcast the wedding service, and it was anticipated the event would be watched by hundreds of millions of people worldwide on television.