As of 2026-10-12, Royal Horticultural Society tops the list with 1,267 employees.
- #1 Royal Horticultural Society — 1,267 employees
registered charity in the UK which promotes gardening and horticulture
The Royal Horticultural Society (RHS), founded in 1804 as the Horticultural Society of London, is the UK's leading gardening charity. Read more on Wikipedia.
Wikidata - #2 Institute of Electrical and Electronics Engineers — 1,000 employees
American professional association for electronic engineering and electrical engineering
The Institute of Electrical and Electronics Engineers is an American 501(c)(3) charitable professional organization for electrical engineering, electronics engineering, and related disciplines. Read more on Wikipedia.
Wikidata - #3 Institute of Physics — 677 employees
GB learned society and professional body
The Institute of Physics (IOP) is a UK-based not-for-profit learned society and professional body that works to advance physics education, research and application. Read more on Wikipedia.
Wikidata - #4 Royal Society of London — 291 employees
English learned society for science
The Royal Society of London for Improving Natural Knowledge, commonly referred to as the Royal Society, is a learned society and the United Kingdom's national academy of sciences. The society fulfils a number of roles: promoting science and its benefits, recognising excellence in science, supporting outstanding science, providing scientific advice for policy, education and public engagement and fostering international and global co-operation. Founded on 28 November 1660, it was granted a royal... Read more on Wikipedia.
Wikidata - #5 Royal Zoological Society of South Australia — 250 employees
Australian organization that operates two zoos
The Royal Zoological Society of South Australia is a non-profit organisation dedicated to the conservation of wildlife and their habitats, education, and research. The society is located in Adelaide, South Australia, and it operates two zoos in South Australia: Adelaide Zoo and Monarto Safari Park. Read more on Wikipedia.
Wikidata - #6 Canadian Federation for the Humanities and Social Sciences — 174 employees
organization for researchers in the humanities and social sciences in Canada
The Canadian Federation for the Humanities and Social Sciences, also known as the Federation for the Humanities and Social Sciences, is a member-based organization and the national voice for researchers in the humanities and social sciences in Canada. Formed in 1996 through a merger of the Social Science Federation of Canada and the Canadian Federation for the Humanities, it is a non-profit charitable organization that represents more than 85,000 researchers in 81 scholarly associations, 80... Read more on Wikipedia.
Wikidata - #7 British Academy — 164 employees
learning society in the UK
The British Academy is the United Kingdom's national academy for the humanities and the social sciences. It was established in 1902 and received its royal charter in the same year. It is now a fellowship of more than 1,000 leading scholars spanning all disciplines across the humanities and social sciences and a funding body for research projects across the United Kingdom. The academy is a self-governing and independent registered charity, based at 10–11 Carlton House Terrace in London. Read more on Wikipedia.
Wikidata - #8 Academy of Medical Sciences — 96 employees
British academic society
The Academy of Medical Sciences is an organisation established in the UK in 1998. It is one of the four UK National Academies, the others being the British Academy, the Royal Academy of Engineering and the Royal Society. Read more on Wikipedia.
Wikidata - #9 Royal Agricultural Society of Victoria — 71 employees
The Royal Agricultural Society of Victoria was founded in 1848, when a group of Melbourne's leading citizens formed the Agricultural Society of Victoria with the aim of "furthering the quality of Australia's primary production by means of contests and competitions". Read more on Wikipedia.
Wikidata - #10 Geological Society of London — 60 employees
learned society
The Geological Society of London, known commonly as the Geological Society, is a learned society based in the United Kingdom. It is the oldest national geological society in the world and the largest in Europe, with more than 12,000 Fellows. Read more on Wikipedia.
Wikidata