Audio description (AD), also referred to as a video description, described video, or visual description, is a form of narration used to provide information surrounding key visual elements in a media work (such as a film or television program, or theatrical performance) for the benefit of blind and visually impaired consumers. These narrations are typically placed during natural pauses in the audio, and sometimes overlap dialogue if deemed necessary. Occasionally when a film briefly has subtitled dialogue in a different language, the narrator will read out the subtitles.

In museums or visual art exhibitions, audio described tours (or universally designed tours that include description or the augmentation of existing recorded programs on audio- or videotape), are used to provide access to visitors who are blind or have low vision. Docents or tour guides can be trained to employ audio description in their presentations.

In film and television, description is typically delivered via a secondary audio track. In North America, Second audio program (SAP) is typically used to deliver audio description by television broadcasters. To promote accessibility, broadcast regulations in some countries have implemented requirements for broadcasters to air specific quotas of programming containing audio description.

The transition to "talkies" in the late 1920s resulted in a push to make the cinema accessible to the visually impaired. The New York Times documented the "first talking picture ever shown especially for the blind"—a 1929 screening of Bulldog Drummond attended by members of the New York Association for the Blind and New York League for the Hard of Hearing, which offered a live description for the visually-impaired portion of the audience. In the 1940s and 1950s, Radio Nacional de España aired live audio simulcasts of films from cinemas with descriptions, framing these as a form of radio drama before television services launched in the country.

In the 1980s, the Media Access Group of U.S. public television station WGBH-TV (which had already gained notability for their involvement in developing closed captioning) developed an implementation of audio description for television programming via second audio program (SAP), which it branded as "Descriptive Video Service" (DVS). It was developed in consultation with Dr. Margaret Pfanstiehl of Washington, D.C., who had performed descriptions at theatrical performances and had run a radio reading service known as the Washington Ear. After four years of development and on-air trials (which included a proof of concept that aired the descriptions on a radio station in simulcast with the television airing), WGBH officially launched audio description via 32 participating PBS member stations, beginning with the new season of American Playhouse on January 24, 1990.

In the 1990s at cinemas in California, RP International began to offer audio descriptions for theatrical films under the brand TheatreVision, relayed via earpieces to those who request it. A clip from Schindler's List was used to pitch the concept to the film's producers Gerald Molen and Branko Lustig, and one of the first films to be presented in this format was Forrest Gump (1994). TheatreVision sought notable personalities and celebrities to volunteer in providing these narrations, such as sportscaster Vin Scully, William Shatner, Monty Hall, and former U.S. president George H. W. Bush (for It's a Wonderful Life). Sometimes the narrator had ties to the film or was part of its cast; Irene Bedard described Pocahontas—a film where she had voiced the title character. For the 1994 remake of Little Women, stars from previous versions of the film volunteered, including June Allyson, Margaret O'Brien, and Janet Leigh (whose grandmother was blind) from the 1949 version of the film, as well as Katharine Hepburn—star of the 1933 version. Other companies emerged in providing descriptions for programming in the U.S., including the National Captioning Institute, Narrative Television Network, and others.

In the UK Audio Description services were made available on the BBC and ITV after a collaborative project with industry partners. In 2000, the BBC voluntarily committed to providing descriptions for at least 20% of its programming annually. In practice, the BBC has often exceeded these targets. In 2009, BBC iPlayer became the first streaming video on-demand service in the world to support AD where every programme that was broadcast with AD also had AD on BBC iPlayer. On January 29, 2009, The Accessible Channel was launched in Canada, which broadcasts "open" audio descriptions on all programming via the primary audio track. Audio description has also been extended to live events, including sporting events, the ceremonies of the Olympic and Paralympic Games, and the royal wedding of Prince William and Catherine Middleton, among others.

In April 2015, the subscription streaming service Netflix announced that it had added support for audio description, beginning with Daredevil—a series based on a comic book character who himself is blind, and would add descriptions to current and past original series on the platform over time. The following year, as part of a settlement with the American Council of the Blind, Netflix agreed to provide descriptions for its original series within 30 days of their premiere, and add screen reader support and the ability to browse content by availability of descriptions.