The University of Calcutta, informally known as Calcutta University (CU), is a public state research university located in Kolkata, also known as Calcutta, in West Bengal, India. It has 151 affiliated undergraduate colleges and 16 institutes in Kolkata and nearby areas. It was established on 24 January 1857 and is the oldest multidisciplinary university of the Indian Subcontinent and the Southeast Asian Region. Today, the university's jurisdiction is limited to a few districts of West Bengal, but at the time of its establishment, it had a catchment area ranging from Kabul to Myanmar. It is accredited as an "A" grade university by the National Assessment and Accreditation Council (NAAC).

The university has a total of fourteen campuses spread over the city of Kolkata and its suburbs. Since 2020, 151 colleges and 21 institutes, and centres have been affiliated with CU. The university was fourth in the Indian University Ranking 2021 list, released by the National Institutional Ranking Framework of the Ministry of Education.

Its alumni and faculty include several heads of state and government, social reformers, prominent artists, the only Indian Dirac Medal winner, many Fellows of the Royal Society, and six Nobel laureates as of 2025. The Nobel laureates associated with this university are Ronald Ross, Rabindranath Tagore, C. V. Raman, Amartya Sen, and Abhijit Banerjee.

The university has the highest number of students who have cleared the National Eligibility Test. The University of Calcutta is a member of the United Nations Academic Impact.