King's College London (informally King's or KCL) is a public research university located in London, United Kingdom and a constituent college of the federal University of London. King's has a claim to being the third-oldest university in England, having been founded by King George IV and the Duke of Wellington in 1829 and received its royal charter in 1836. In 1836 King's became one of the two founding colleges of the University of London.

King's is organised into nine Schools of Study, spread across four Thames-side campuses in central London and one in Denmark Hill, South London. It is one of the largest centres for graduate and post-graduate medical teaching and biomedical research in Europe; it is home to six Medical Research Council centres, the most of any British university, and is a founding member of the King's Health Partners academic health sciences centre. King's has around 18,600 full-time students and 5,030 staff and had a total income of £524.1 million in 2010/11, of which £147.1 million was from research grants and contracts.

King's is ranked 63rd in the world (and 16th in Europe) in the 2010 Academic Ranking of World Universities, 21st in the world (and 6th in Europe) in the 2010 QS World University Rankings, and 77th in the world (and 15th in Europe) in the 2010 Times Higher Education World University Rankings. There are currently 10 Nobel Prize laureates amongst King's alumni and current and former faculty. In September 2010, The Sunday Times selected King's as its "University of the Year".

King's is a member of the Association of Commonwealth Universities, the European University Association, the Russell Group and Universities UK. It forms part of the 'Golden Triangle' of British universities.