Voice-Over (VO or V/O), is the speaking of a person or presenter (announcer, reporter, anchor, commentator, etc.) who is not seen on the screen while her or his voice is heard. Occasionally, a narrator may be seen in a shot but not speaking the words heard in the voice-over.

Voice-over has diverse uses in a variety of television genres. Like other forms of television talk, it aims at being informal, simple and conversational. However, except for on-the-spot reporting such as sports events, voice-over is often less spontaneous than the language of talk shows; it is heavily scripted especially in genres such as the documentary. Voice-over is not simply descriptive; it also contextualizes, analyses and interprets images and events. Commentaries have the power to reverse the significance of a particular visual content. Voice-over is, therefore, an active intervention or mediation in the process of generating and transmitting meaning. However, viewers are rarely aware or critical of the scope of mediation in part because the visual image itself confers credibility and authenticity on the voice-over. But voice is at times more credible than vision; it is an integral part of a person's identity. This was experienced in the 1988 British government ban on broadcast interviews with representatives of eleven Irish organizations, including Sinn Fein, the political wing of the Irish Republican Army. Broadcasters were allowed, however, to voice-over or caption a banned representative's words.

Voice-over is used as a form of language transfer or translation. Viewers of news programs are familiar with the voice-over translation of statements or responses of interviewees who do not speak in the language of the viewing audience. Inherited from radio, this form of language transfer allows the first and last few words in the original language to be heard, and then fades them down for revoicing a full translation. The voice-over should be synchronous with the speaker's talk, except when a still picture is used to replace footage or live broadcast. Usually gender parity between the original and revoiced speakers is maintained.

As a form of language transfer, voice-over is not limited to the translation of brief monologues; sometimes it is used to cover whole programs such as parliamentary debates, conferences or discussions. Its production is usually less expensive than dubbing and subtitling. Some countries, such as Poland and the Balkan states, use voice-over as the main method of revoicing imported television programs. Usually, the revoicing is done without much performance or acting, even when it involves drama genres.

-Amir Hassanpour