UCL opened in Bloomsbury in February 1826 as London University, a joint-stock venture backed by reformers drawn to the utilitarian thinking of Jeremy Bentham. Conceived as an alternative to Oxford and Cambridge, it enrolled students without reference to religious affiliation, breaking with the Anglican requirements that governed English higher education at the time. Political resistance denied it degree-awarding powers, and in 1836 its proprietors accepted incorporation as University College, London, becoming one of the two founding colleges of the chartered University of London. UCL remains a member of that federal university while operating as a separate institution; a supplemental charter sealed in 2023 granted it university status in its own right.

Teaching and research are organised into eleven faculties holding more than a hundred departments, institutes and research centres. They span arts and humanities, laws, social and historical sciences, mathematical and physical sciences, engineering, life sciences, medical sciences, population health sciences and brain sciences, alongside the Bartlett faculty of the built environment and the IOE faculty of education and society. Several units arrived through mergers with specialist London bodies, among them the Institute of Neurology, the School of Pharmacy and the Institute of Education. Enrolment reached 51,315 students in 2024/25, split almost evenly between undergraduate and postgraduate study.

Research is central to the institution: of a total income near GBP 2.16 billion in 2024/25, some GBP 556.6 million came from research grants and contracts awarded by research councils, British charities and other funders. UCL belongs to the Russell Group and the League of European Research Universities, and forms part of UCL Partners, an academic health science centre tying it to associated teaching hospitals. Its main estate lies in Bloomsbury, in the London Borough of Camden, around Gower Street and the Grade I listed Wilkins building, with medical institutes beside partner hospitals in Queen Square. A second campus, UCL East, opened at Queen Elizabeth Olympic Park in Stratford from 2022.