The Derby Assembly Rooms was an events venue in the English city of Derby. There have been three iterations of the Derby Assembly Rooms, with the last two on the same site. The first was opened in 1714 in Full Street, but soon proved inadequate. The second was built in 1763 on Market Place and was used until it was damaged by a fire in 1963. The third was built in 1977 and used until it too was damaged in a fire in 2014.

Both of the last two buildings still exist, at least in part. The façade of the 1763 building was dismantled and rebuilt as part of the vintage street scene at the National Tramway Museum in Crich, Derbyshire. The 1977 building still stands, albeit unused since 2014, but has an uncertain future.

The first assembly rooms in Derby were opened in 1714 in Full Street. However, the premises used were rather small and not of particularly striking appearance, so it was not long before they were considered unsuitable for the assemblies. Later the building was converted into a permanent theatre, which became known as the Little Theatre in Full Street.

As a replacement for the first building, the 1763 building was built by the architect Joseph Pickford on a site gifted by the Duke of Devonshire and using funds raised by public subscription. It was managed by a board of trustees and contained various rooms, including a ballroom, with room for 400 people, and a supper room. The rooms were used for hosting balls, auctions, banquets, and private functions.

In the 1920s, Derby Corporation wanted to compulsorily purchase the Assembly Rooms, but this was opposed by the trustees. After negotiations, the building was acquired by the Corporation for £8167. It was agreed that the façade would be re-erected elsewhere, and that an alternative venue would be provided. Despite this agreement, the building remained standing and in use until it was damaged in a fire in 1963.

Because of the 40-year-old agreement, the façade was then dismantled and re-erected at the National Tramway Museum, which is some 18 kilometres (11 mi) north of its original site, in the Derbyshire village of Crich. Here a modern building behind the re-erected façade houses the museum's small-exhibits exhibition space and library. The re-erected building was opened by the Duke of Gloucester in 1976.

The 1977 building was designed by Hugh Casson and Neville Conder in the brutalist style.

The venue has seen performances by Elton John, Iron Maiden, Judas Priest, Take That, the Manic Street Preachers, Tony Bennett and Frankie Laine. It is also notable as the original home of Bloodstock Festival which began there as a one-day indoor event.

The building has been closed since a 2014 fire in the plant room of an adjacent multi-storey car park damaged the Assembly Rooms' ventilation system. Historic England issued a Certificate of Immunity from Listing in April 2023, guaranteeing that the building would not be statutorily listed within the next five years.

In October 2023 a council-led investigation was announced into why the complex had lain unused for 10 years. A council leader commented that £20 million levelling up funding awarded from April 2023 was insufficient to cover demolition and replacement with a new theatre.