The Queen will step down as patron of 25 national organisations at the end of this year, says Buckingham Palace.
The patronages, including the NSPCC, Save the Children, Barnardo's and Battersea Dog's Home, will be passed on to other members of the Royal Family.
Rugby Football Union, the Lawn Tennis Association and the Royal Geographical Society are also affected.
The Queen is royal patron of more than 600 bodies - 433 of which she has been patron of since 1952.
Buckingham Palace said the announcement was the start of a process that would see patronages passed on to other Royal Family members in the coming months.
The Queen will continue to serve as patron to hundreds of charities and institutions but will now share this work with her family, the palace added.
This move follows the example set by the Duke of Edinburgh who resigned from a number of patronages around his 90th birthday in 2011.
'Easing the load'
By Peter Hunt, BBC royal correspondent
This is an acknowledgement of advancing age.
Palace officials are characterising it as a gradual lightening of the Queen's load and such lightening has been going on for some time, with no fanfare.
It's an inevitable course of action when retirement is not an option.
She's undertaking fewer public engagements - 196 in the UK in 2014-15 and 177 in the following 12 months.
The Queen is unlikely to fly long-haul ever again seeing as Prince Harry represented her in the Caribbean last month. Prince Charles will also probably be in Canada, in place of his mother, next year.
And the challenge for a nonagenarian of standing for up to an hour at an investiture is eased by the fact other royals also conduct some of the ceremonies.
In the coming months and years, the Queen will continue to delegate duties to members of her family.
She will also continue to reign.
Other organisations which will be seeking a new patron include the Wildfowl and Wetlands Trust, the Royal School of Needlework, the Royal African Society, the British Science Association, the Institution of Civil Engineers, the Animal Health Trust and the Royal Geographical Society.
Prince Charles will replace the Queen as patron of the Holocaust Day Memorial Trust and the Royal Institution, while the Duchess of Cornwall will take over at children's charity Barnardo's.
The Countess of Wessex will take on the role of patron at the NSPCC and at Blind Veterans UK - a role which the Queen had taken over from her father in 1952.
Prince William will replace the Queen as patron of the Amateur Swimming Association while Prince Harry will become patron of the Rugby Football Union and the Rugby Football League. The Duchess of Cambridge will take over the role at the All England Lawn Tennis and Croquet Club (AELTC) in Wimbledon.
The announcement came as members of the Royal Family gathered at Buckingham Palace to begin their Christmas celebrations.
The Queen and Duke of Edinburgh traditionally host a festive lunch for their family before leaving for their private Sandringham estate, where they spend the holidays.
Prince William was seen arriving with the Duchess of Cambridge, Prince Harry and three-year-old Prince George.
The royal trio carried out their last official engagement of the year on Monday, joining a Christmas party in London for their mental health campaign organisation Heads Together.