Approximately 8,000 guests attend each garden party. People from all walks of life are invited on the recommendation of a large number of national organisations who submit lists on a pre-arranged quota. For example, the government, Lord-Lieutenants and organisations such as the Civil Service, Armed Services, Diplomatic Corps, charities and societies, all have quotas for nominations. This ensures that a representative cross-section of the community is invited and that guests are generally people who have contributed a large amount to their various organisations or society.

Garden party invitations are sent out by the Lord Chamberlain' s Office in the Lord Chamberlain's name on behalf of The Queen. All the arrangements are planned by the Lord Chamberlain's Office.

Special Garden Parties
Every year, there is also a garden party for the Not Forgotten Association, a charity for war veterans of all ages, which is hosted by a member of the Royal Family, often The Princess Royal who is Patron of the organisation.

The Queen gives permission for additional garden parties to be held to honour large national organisations celebrating a special event, such as the Territorial Army’s 100th anniversary, the centenary of the British Red Cross's Royal Charter, or the Lambeth Conference. These are often attended by Her Majesty or another member of the Royal Family.

In 1997 The Queen and The Duke of Edinburgh hosted a garden party for couples sharing their Golden Wedding anniversary (50 years of marriage) with them. In 2002 special garden parties held at Buckingham Palace and the Palace of Holyroodhouse included garden parties for individuals born on 6 February 1952, the day of Her Majesty's Accession.

The Duke held garden parties for the 50th anniversary of The Duke of Edinburgh's Award Scheme in 2006 and, in 2007, for the centenary of the Caravan Club, of which His Royal Highness is President.