The Golden Jubilee is a focus for many events
She will be paying a visit to the Royal School, in Windsor, on Thursday.
It comes after the Queen resumed official duties on Wednesday night when she hosted a Golden Jubilee reception and dinner at Windsor bringing together all her Commonwealth representatives for the first time.
Also present was the Prince of Wales, who earlier in the day spoke of how much he missed his grandmother when he made his first public appearance since her funeral.
Unique
Ahead of the official Royal mourning period ending on Friday, the events mark the restarting of the Queen's busy calendar following her mother's death on 30 March.
At Wednesday's unique reception and dinner, in the Waterloo Chamber at Windsor Castle, she welcomed 15 governor-generals of Commonwealth countries.
Other members of the Royal Family were also there, including the Duke of York, Princess Royal with her husband Commodore Timothy Laurence, and the Earl and Countess of Wessex.
After the meal, guests were invited inside the Royal Library, home to many treasures, books and illuminated manuscripts.
Earlier Prince Charles had spoken of how touched he felt by the "extraordinary outpouring of affection and devotion" shown by members of the public at his grandmother's funeral.
'Huge interest'
Talking to young entrepreneurs at a ceremony for the Prince's Trust business awards, he said: "The saddest thing for me is not being able to go and talk to her afterwards about something like this.
"She always took a huge interest in the things I was trying to do."
His appearance marked the end of his grieving retreat at Balmoral in Scotland, where he flew one week ago, after the funeral.
"I shall miss her more than I could possibly say and I'm so grateful to so many people who have written in and shown such incredible sympathy, and said so many marvellous things," he said.
Later on Wednesday, the Prince of Wales also presented actors, architects, celebrities and business personalities with OBEs at an investiture at Buckingham Palace.