Some 300,000 people are expected over five days at the world-famous annual meet, where the Queen arrives each day by horse-drawn carriage.
Attracting some of the best thoroughbreds, jockeys and trainers in the world, it is also known for its display of flamboyant and exotic hats, with the most extravagant creations making an appearance on Ladies’ Day on Thursday.
Wearing a fuchsia and cerise-coloured outfit, the Queen arrived this afternoon in a carriage with the Duke of Edinburgh, Prince Harry and the Duke of York.
The Prince of Wales, Duchess of Cornwall and Princess Beatrice followed in the second carriage, while the Princess Royal rode in the third carriage.
The male royals wore morning dress with a waistcoat and top hat. Writing in the foreword to the official programme, the Queen said Royal Ascot had become a “wonderful spectacle shared with the whole world”.
She said: “At the turn of the millennium, Royal Ascot was very much a European affair, but now we share the wonderful spectacle with the world.
“We have horses representing many countries in front of an audience, both here at Ascot and watching at home, from far and wide.
“It gives me great pleasure to hear how much the racing community looks forward to Royal Ascot. I know the thrill that participation as a racehorse owner brings, and I wish all those with runners in the 30 races the very best of luck.”
The Queen unveiled a new statue of five-times Ascot winner Frankel after the opening race, the Queen Anne Stakes.
Frankel, who was trained by the late Sir Henry Cecil and is widely acknowledged as the greatest racehorse of the modern era, retired unbeaten following a 14-race career in October 2012.
The bronze statue, created by sculptor Mark Coreth, overlooks the parade ring, facing the winners’ enclosure.
Sir Henry’s widow Lady Cecil said: “Ascot played a special part in Frankel’s career as five of his 14 wins came at the course. It is fitting that such a magnificent statue will stand at the course to celebrate his achievements.
“Mark Coreth has captured the presence, power and strength of Frankel. I cannot imagine a more fitting or appropriate testament to his talent.”