Michaelhouse is a former college of the University of Cambridge, that existed between 1323 and 1546, when it was merged with King's Hall to form Trinity College. Michaelhouse was the second residential college to be founded, after Peterhouse (1284). Though King's Hall was established earlier in 1317, it did not acquire actual premises until its re-foundation by Edward III in 1336. The name Michaelhouse is now used for St Michael's Church.

Established formally on Michaelmas Day 1324 as a college for scholars in Holy Orders, Michaelhouse is named after the parish church of the same name located on Cambridge's magna strata or High Street (today's Trinity Street). Founded by Hervey de Stanton, Edward II's Chancellor of the Exchequer and Lord Chief Justice (Chief Justice of the Pleas) of England, the college was established between spring 1323 and autumn 1324. On 28 May 1323, de Stanton obtained from Dera de Madingley the advowson (or right of presentation) to the parish of St Michael as well as her messuage on the High Street 'for a hundred silver marks.' On 16 March 1323/4, de Stanton purchased for another hundred silver marks an extensive property located on St Michael's Lane, complete with walled garden and a quay on the wharves of the River Cam owned by Robert Buttetourte.

In May 1324, Edward II granted a royal charter to the new college. On 31 August 1324, the Bishop of Ely, John Hotham, granted his own charter. The following day, John de Crauden, prior of the monastic foundation of Ely, added his agreement under the chapter seal. King, bishop and prior left de Stanton free hand in the appointment of the college’s first Master and the drafting of statutes for his college. On Michaelmas Day that year, Walter de Buxton, priest, was appointed the College's first Master.

On 11 November 1324 Hervey de Stanton obtained the properties of Adam de Trumpington, rector of Buckland, for his college. At about the same time, he ordered the rebuilding of the parish church in the Decorated style for use as a chapel. Following his death on All Souls' Day 1325, de Stanton was buried in the unfinished chancel. His executors, John de Illegh and Alexander Walsham, continued the expansion of the College by purchasing further properties between St Michael's Lane (today's Trinity Lane), and the river, an area now occupied by the southwest corner of Trinity's Great Court, and Neville Court. These included the purchase, in 1329, of two hostels South of St Michael's lane and Milne Street (today's Trinity Hall Lane), Ovyng and Garret Hostel. The latter gave its name to the lane leading to the river.

At Michaelmas 1337, de Illegh acquired another hall of residence adjacent to the King's Hall, known as Crouched Hall or Newmarket Hostel. Two properties located on St Michael's Lane complete the early expansion: the bequest by Joan de Refham in 1549 of her home and shops led to the establishment of St Katherine's Hostel, and the acquisition in 1353 of a house owned by Archdeacon of Norfolk that gave way to St Gregory's Hostel. The latter almost certainly took its name from the dedication of one of the chapels at St Michael's Church. By the mid-14th century, Michaelhouse took up most of the present south-west corner of Trinity College's Great Court and New Court, further acquiring lands now occupied by Trinity's Scholars' Lawn and the Wren Library. The college's core property included a navigable stream and a ditch which formed a natural boundary with the adjacent common, and the King's Hall. The College benefited from a number of other local properties and further endowments. Indeed, although its buildings were never grand but of a size suitable to the small fellowship (the Hall measured only around 26 metres by 12 metres), by the time of its dissolution Michaelhouse had an annual income in excess of £140, some £50 higher than that of St Peter's Monastery in Westminster (Westminster Abbey).

Walter de Buxton, priest, 1324
Henry Granby, fl. 1418
John Fisher, 1497-1505

Throughout its existence, the college remained a study house for clergy with a conservative theological ethos. The main exponent of this thinking is probably John Fisher, who served as Master between 1497 and 1505. As Chancellor of the university, Fisher was instrumental in the foundation of St John's and Christ's. As Bishop of Rochester he maintained the conservative stance on the royal supremacy and the reformation measures of king Henry VIII shared by much of the Michaelhouse fellowship which, more prominent and vociferous in his case, ultimately led to Fisher's execution in 1535.

Ironically, Henry VIII made use of the same measures challenged by the Michaelhouse fellowship to dissolve the college. Following the dissolution of religious houses in England, Cambridge University rightly feared for the future of its colleges, many of which were religious foundations or study houses for clergy. The university was able to make use of its contacts to petition the queen, Katharine Parr who, in turn, persuaded Henry to spare most colleges. Indeed, the two colleges facing dissolution, together with vast tracts of land acquired from the dissolution of the monasteries, would eventually endow a new royal foundation befitting his grandeur. Consequently, in 1546 Michaelhouse was dissolved by act of Parliament, and merged with its neighbour King's Hall to form Trinity College. Further endowed by Mary Tudor and Elizabeth I, Trinity remains one of the largest colleges and the wealthiest college in the university.