The Donmar Warehouse is a 251-seat, not-for-profit theatre in Covent Garden, London, England. It first opened on 18 July 1977. Sam Mendes, Michael Grandage and Josie Rourke have all served as artistic director, a post held since 2019 by Michael Longhurst. The theatre has a diverse artistic policy that includes new writing, contemporary reappraisals of European classics, British and American drama and small-scale musical theatre. As well as presenting at least six productions a year at its home in Covent Garden, every year the Donmar tours one in-house production in the UK.

Theatrical producer Donald Albery formed Donmar Productions around 1953, with the name derived from the first three letters of his name and the first three letters of his wife's middle name, Margaret. In 1961, he bought the warehouse, a building that in the 1870s had been a vat room and hops warehouse for the local brewery in Covent Garden, and in the 1920s had been used as a film studio and then the Covent Garden Market banana-ripening depot. His son Ian Albery, a producer and theatre design consultant, converted the warehouse into a private rehearsal studio.

In 1977, the Royal Shakespeare Company acquired it as a theatre and renamed it the Warehouse, converting and equipping at "immense speed". The first show, which opened on 18 July 1977, was Schweik in the Second World War, directed by Howard Davies, which transferred from the Other Place in Stratford. The electricity for the theatre was turned on just 30 minutes before curtain up, and the concrete steps up to the theatre were still wet.

The Warehouse was an RSC workshop as much as a showcase and the seasons were remarkably innovative, including Trevor Nunn's acclaimed Stratford 1976 Macbeth, starring Judi Dench and Ian McKellen, which opened at the Covent Garden venue in September 1977 before transferring to the Young Vic. The RSC went on to stage numerous acclaimed productions, both original and transfers from The Other Place, Stratford. In 1980 nearly all the RSC company were involved in Nicholas Nickleby so a new two hander was found from the pile of submitted scripts. Educating Rita, with Julie Walters and Mark Kingston directed by Mike Ockrent, went on to be one of the RSC's biggest successes.

From 1983 to 1989 it came under the artistic directorship of Nica Burns.

In 1990, Roger Wingate was responsible for the acquisition of the Donmar Warehouse. He completely rebuilt and re-equipped it in the form it is known today. Prior to its reopening in 1992, Roger Wingate appointed Sam Mendes as the theatre's first Artistic Director. As a board member and theatrical producer, Roger Wingate remains closely involved with the Donmar to the present day.