Trinity College is a constituent college of the University of Cambridge. Founded in 1546 by King Henry VIII, Trinity is one of the largest Cambridge colleges, with the largest financial endowment of any college at Oxford or Cambridge. Trinity has some of the most distinctive architecture in Cambridge with its Great Court said to be the largest enclosed courtyard in Europe. Academically, Trinity performs exceptionally as measured by the Tompkins Table (the annual unofficial league table of Cambridge colleges), coming top from 2011 to 2017, and regaining the position in 2024.

Members of Trinity have been awarded 34 Nobel Prizes out of the 121 received by members of the University of Cambridge (more than any other Oxford or Cambridge college). Members of the college have received four Fields Medals, one Turing Award and one Abel Prize. Trinity alumni include Francis Bacon, six British prime ministers (the highest number of any Cambridge college), physicists Isaac Newton, James Clerk Maxwell, Ernest Rutherford and Niels Bohr, mathematicians Srinivasa Ramanujan and Charles Babbage, poets Lord Byron and Lord Tennyson, English jurist Edward Coke, writers Vladimir Nabokov and A. A. Milne, historians Lord Macaulay and G. M. Trevelyan, and philosophers Ludwig Wittgenstein and Bertrand Russell (who the college expelled before reaccepting). Two members of the British royal family have studied at Trinity and been awarded degrees: Prince William of Gloucester and Edinburgh, who gained an MA in 1790, and King Charles III, who was awarded a lower second class BA in 1970.

Trinity's many college societies include the Trinity Mathematical Society, the oldest mathematical university society in the United Kingdom, and the First and Third Trinity Boat Club, its rowing club, which gives its name to the May Ball. Along with Christ's, Jesus, King's and St John's colleges, it has provided several well-known members of the Cambridge Apostles, an intellectual secret society. In 1848, Trinity hosted a meeting at which Cambridge undergraduates representing fee-paying private schools codified a set of early rules of football known as the Cambridge rules. Trinity's sister college is Christ Church, Oxford. Trinity has been linked with Westminster School since the school's re-foundation in 1560, and its Master is an ex officio governor of the school.

The college was founded by Henry VIII in 1546 with the name College of the Holy and Undivided Trinity within the Town and University of Cambridge of King Henry the Eighth's Foundation, from the merger of two existing colleges: Michaelhouse (founded by Hervey de Stanton in 1324), and King's Hall (established by Edward II in 1317 and refounded by Edward III in 1337). At the time, Henry had been seizing (Catholic) church lands from abbeys and monasteries. The universities of Oxford and Cambridge, being both religious institutions and quite rich, expected to be next in line. The King duly passed an Act of Parliament that allowed him to suppress (and confiscate the property of) any college he wished. The universities used their contacts to plead with his sixth wife, Catherine Parr. The Queen persuaded her husband not to close them down, but to create a new college. The king did not want to use royal funds, so he instead combined two colleges (King's Hall and Michaelhouse) and seven hostels to form Trinity.

The monastic lands granted by Henry VIII were not on their own sufficient to ensure Trinity's eventual rise. In terms of architecture and royal association, it was not until the Mastership of Thomas Nevile (1593–1615) that Trinity assumed both its spaciousness and its association with the governing class that distinguished it since the Civil War. In its infancy Trinity had owed a great deal to its neighbouring college of St John's: in the words of Roger Ascham, Trinity was a colonia deducta.

Most of Trinity's major buildings date from the 16th and 17th centuries. Thomas Nevile, who became Master of Trinity in 1593, rebuilt and redesigned much of the college. This work included the enlargement and completion of Great Court and the construction of Nevile's Court between Great Court and the river Cam. Nevile's Court was completed in the late 17th century with the Wren Library, designed by Christopher Wren. Nevile's building campaign drove the college into debt from which it surfaced only in the 1640s, and the Mastership of Richard Bentley adversely affected applications and finances. Bentley himself was notorious for the construction of a hugely expensive staircase in the Master's Lodge and for his repeated refusals to step down despite pleas from the Fellows. Besides, despite not being a sister college of Trinity College Dublin, as is the case with St John's College, Cambridge, it is believed that the Irish institution takes its name from this college, which was the alma mater of its first provost, Adam Loftus and, likewise, from Trinity College, Oxford.

In the 20th century, Trinity College, St John's College and King's College were for decades the main recruiting grounds for the Cambridge Apostles, an elite, intellectual secret society. In 2011, the John Templeton Foundation awarded Trinity College's Master, the astrophysicist Martin Rees, its controversial million-pound Templeton Prize, for "affirming life's spiritual dimension". Trinity is the richest Oxbridge college with a landholding alone worth £800 million. For comparison, the second richest college in Cambridge (St John's) has estimated assets of around £780 million, and the richest college in Oxford (Magdalen) has about £940 million. In 2005, Trinity's annual rental income from its properties was reported to be in excess of £20 million. The college owns:

In 2018, Trinity revealed that it had investments totalling £9.1 million in companies involved in oil and gas production, exploration and refinement. These included holdings of £1.2 million in Royal Dutch Shell, £1.7 million in Exxon Mobil and £1 million in Chevron. In 2019, Trinity confirmed its plan to withdraw from the Universities Superannuation Scheme (USS), the main pre-1992 UK University pension provider. In response, more than 500 Cambridge academics signed an open letter undertaking to "refuse to supervise Trinity students or to engage in other discretionary work in support of Trinity's teaching and research activities". On 17 February 2020, protestors from the campaign group Extinction Rebellion dug up the front lawn of Trinity College to protest against the College's investments in fossil fuels and its negotiations to sell off a farm in Suffolk that was to be turned into a lorry park.