West End theatre is mainstream professional theatre staged in the large theatres in and near the West End of London. Along with New York City's Broadway theatre, West End theatre represents the highest level of commercial theatre in the English-speaking world. Seeing a West End show is a common tourist activity in London. Prominent screen actors, British and international alike, frequently appear on the London stage.

There are about 40 theatres in the West End. The Theatre Royal, Drury Lane, opened in 1663, is the oldest theatre in London. The Savoy Theatre—built as a showcase for the popular series of comic operas of Gilbert and Sullivan—was entirely lit by electricity in 1881.

The Society of London Theatre (SOLT) announced that 2018 was a record year for the capital's theatre industry: attendances topped 15.5 million for the first time since the organisation began collecting audience data in 1986. Box office revenues exceeded £765 million. Attendance slipped 1.4% the next year, but box office revenues reached a record £799 million. In 2023, audiences reached a record 17.1 million.

Most West End theatres are owned by the ATG Entertainment, Delfont Mackintosh Theatres, Nimax Theatres, LW Theatres, and the Nederlander Organization.

Theatre in London flourished after the English Reformation. The first permanent public playhouse, known as The Theatre, was constructed in 1576 in Shoreditch by James Burbage. It was soon joined by The Curtain. Both are known to have been used by William Shakespeare's company. In 1599, the timber from The Theatre was moved to Southwark, where it was used to build the Globe Theatre in a new theatre district beyond the controls of the City corporation.

The Puritans, who regarded theatre as sinful, closed them in 1642. On 24 January 1643, actors protested the ban by writing a pamphlet, "The Actors remonstrance or complaint for the silencing of their profession, and banishment from their severall play-houses".

After the Restoration (1660), Puritan legislation was declared null and void, and theatre (among other arts) exploded. Two companies were licensed to perform: the Duke's Company and the King's Company. Performances were held in converted buildings, such as Lisle's Tennis Court. The first West End theatre, known as Theatre Royal in Bridges Street, was designed by Thomas Killigrew and built on the site of the present Theatre Royal, Drury Lane. It opened on 7 May 1663 and was destroyed by a fire nine years later. It was replaced by a new structure designed by Christopher Wren and renamed the Theatre Royal, Drury Lane. One of the first actresses on the stage, Nell Gwyn became a star of restoration comedy.

Outside the West End, Sadler's Wells Theatre opened in Islington on 3 June 1683. Taking its name from founder Richard Sadler and monastic springs that were discovered on the property, it operated as a "Musick House", with performances of opera; as it was not licensed for plays. In the West End, the Theatre Royal Haymarket opened on 29 December 1720 on a site slightly north of its current location, and the Royal Opera House opened in Covent Garden on 7 December 1732. John Gay's ballad opera The Beggar's Opera ran for 62 performances in 1728, and held the record for London's longest run for nearly a century. It has been called "the most popular play of the eighteenth century." Another musical show, Tom and Jerry, or Life in London (1821), was the first London production to reach 100 consecutive performances. Tom and Jerry's combination of a tour of London interspersed with song and dance, gave rise to numerous similar, loosely constructed entertainments, and "planted the seeds for later musical comedy and revue". In 1823, Presumption; or, the Fate of Frankenstein, the first adaptation of Mary Shelley's Frankenstein, was staged at the English Opera House (renamed the Lyceum Theatre in 1834) by Richard Brinsley Peake, who also introduced the line "It lives!". Shelley attended a performance on 29 August 1823 and following the success of the play she wrote, "lo & behold! I found myself famous!".