•She died with her children gathered around her at her Scottish estate near Aberdeen.
•The Queen had been under medical supervision the entire Thursday at Balmoral after doctors became concerned for her health.
Queen Elizabeth II is dead, Buckingham Palace has confirmed
In a statement, Buckingham Palace said: "The Queen died peacefully at Balmoral this afternoon.
"The King and the Queen Consort will remain at Balmoral this evening and will return to London tomorrow."
All the Queen's children travelled to Balmoral, near Aberdeen, after doctors placed the Queen under medical supervision.
She died with her children gathered around her at her Scottish estate near Aberdeen.
Her grandson, Prince William, is also there, with his brother, Prince Harry, on his way.
The Queen had been under medical supervision the entire Thursday at Balmoral after doctors became concerned for her health.
Buckingham Palace said in a very unusual statement that the 96-year-old monarch was "comfortable".
"Following further evaluation this morning, the Queen's doctors are concerned for Her Majesty's health and have recommended she remain under medical supervision," the statement said.
Prince Charles, the heir apparent, and his wife, Camilla, the Duchess of Cornwall were present when the Queen died.
The Duke of Cambridge, the Duke of York, and the Earl and Countess of Wessex were also present.
Following the death, Prince Charles will on Friday be proclaimed the new official reigning monarch.
The Queen’s funeral is expected to be held 10 days after her death.
Queen Elizabeth II's tenure as head of state spanned post-war austerity, the transition from empire to Commonwealth, the end of the Cold War and the UK's entry into - and withdrawal from - the European Union.
Her reign spanned 15 prime ministers starting with Winston Churchill, born in 1874, and including Liz Truss, born 101 years later in 1975, and appointed by the Queen earlier this week.
She held weekly audiences with her prime minister throughout her reign.
At Buckingham Palace in London, crowds awaiting updates on the Queen's condition began crying as they heard of her death.
The Queen was born Elizabeth Alexandra Mary Windsor, in Mayfair, London, on 21 April 1926.
Additional reporting by BBC