Voice acting is the art of providing voices for animated characters (including those in feature films, television series, animated shorts, and video games) and radio and audio dramas and comedy, doing voice-overs in radio and television commercials, audio dramas, dubbed foreign language films, video games, puppet shows, and amusement rides.

Performers are called voice actors, voice actresses or voice artists, and may also involve singing, although a second voice actor is sometimes cast as the character's singing voice. Voice artists are also used to record the individual sample fragments played back by a computer in an automated announcement system. At its simplest, this is just a short phrase which is played back as necessary, e.g. the Mind the gap announcement introduced by London Underground in 1969. In a more complicated system such as a speaking clock, the voice artist usually doesn't actually record 1440 different announcements, one for each minute of the day, or even 60 (one for each minute of the hour), instead the announcement is re-assembled from fragments such as "minutes past" "eighteen" and "pm". For example, the word "twelve" can be used for both "Twelve O'Clock" and "Six Twelve". So far voice artists have been preferred to speech synthesis because they sound more natural to the listener.

A list of voice acting by one voice actor, one director, or on one subject, is sometimes called a voxography.

In the United States

Broadcast media

For live-action production, voice acting often involves reading the parts of computer programs (Douglas Rain; Majel Barrett), radio dispatchers (Shaaron Claridge), or characters who never actually appear on screen but who give instructions by telephone (John Forsythe in Charlie's Angels), or mailed recording (Bob Johnson in Mission: Impossible). "Stunt double" voice actors are sometimes employed; if a voice actor or actress loses his or her voice, someone who sounds similar can step in. For example, when Jeremy Irons' vocal cords became strained during the recording of the Lion King's song "Be Prepared", Jim Cummings was called in to finish the song.

It is not unusual to find among the ranks of voice actors people who also act in live-action film or television, or on the stage (see e.g., J. Scott Smart, an "old time radio" actor). For those actors, voice acting has the advantage of offering acting work without having to bother with makeup, costuming, lighting, and so on. An occasional advantage is the fact that through voice acting, an actor can reprise a role that he has played in live action but would be otherwise too aged to portray. An example of this is Walter Koenig in Star Trek New Voyages who reprises his role as Lt. Pavel Chekov.

A common practice in animation is to cast a woman to play the role of a young boy. On The Simpsons, for example, Nancy Cartwright plays Bart Simpson and several other juvenile males. Other voice actresses who would fit this criterion are Tara Strong, who voices Timmy Turner and Poof and other young boys on The Fairly OddParents, and she voices other young boys on other TV shows, or Regina King as the voice of Huey and Riley Freeman on the Adult Swim show The Boondocks. This casting practice goes back to at least 1939, with Bernice Hansen as Sniffles the Mouse, and continues with Elizabeth "E. G." Daily as Tommy Pickles on Rugrats and All Grown Up! today. June Foray, even as a senior citizen, can still faithfully voice Rocket J. Squirrel. Casting adult women for these parts can be especially useful if an ad campaign or a developed series is expected to run for several years, for while the vocal characteristics of a male child actor would change over time, the voice of an adult female will not.

A notable exception to using women to voice young boys' roles is the Peanuts animated features, in which boys were actually cast to read the boys' lines (e.g., Charlie Brown, Linus, Schroeder). In South Park, the authors Trey Parker and Matt Stone are also voice actors for most male roles, especially the boys: Parker voices Stan, Cartman and others while Stone is the voice of Kyle, Kenny, Butters and others. South Park kids' voices are pitched up a little in order to seem more "childish". In addition, kindergarten kids on the show are voiced by actual young children for realism.

Rise in use of film actors for voice roles

For much of the history of North American animation, voice actors had a predominantly low profile as performers, with Mel Blanc the major exception. Over time, many movie stars began voice acting in movies, with one of the earliest examples being The Jungle Book, which counted among its cast contemporary stars such as Phil Harris, Sebastian Cabot, Louis Prima, George Sanders and Sterling Holloway. The film which truly brought about this modern perception, however was Aladdin which was marketed with a noted emphasis on Robin Williams' role. The success of this film eventually spurred the idea of highlighting the voice actors as stars of a film, this becoming the norm in movie marketing, with a greater focus on hiring Hollywood celebrities for name power, rather than performers with more experience in voice acting. By contrast, using anime voice actors as a box office draw was developed far earlier in Japan.
Some voice actors, such as Billy West, are highly critical of using movie stars for voices in animated features. A particular point of contention is the practice of bringing in veteran voice actors (who are capable of greatly altering their voices and inflections in order to create personalities for characters) to read for a part, and then use the recording of the professional voice actor as a guide for the movie star, even though the actual character creation work is being done by the unpaid voice actor. West struck back at this practice in Comic Book: The Movie, in which the entire main cast comprises voice actors, including Jess Harnell, Lori Alan, Daran Norris, Mark Hamill and Tom Kenny. The practice of hiring singers to "fill in" for voice actors in a singing role has also seen change, as both Jeremy Irons and Mel Gibson have done singing in the respective films The Lion King and Pocahontas, rather than have a singer as substitute.

Voice actors have a relatively small but dedicated fan base, with appearances at large events like Comic-Con International, various anime conventions, and websites dedicated to profiling their work.

Commercials for television and radio are also cast using voice acting agencies. Ernie Anderson was one of radio's most prominent voices throughout the 1970s and 1980s and was heard on radio stations across the United States. While Don LaFontaine filled the category of "The Voice of God" until his death in 2008, Ashton Smith, Howard Parker and Miguel Ferrer provide most of the narration for movie trailers. Sylvia Villagran is one of the few women working in movie trailers today. Beginning in the early 2000s, many organizations have moved toward a younger, more natural sound; a few notable voice actors in this category are Rick Robles (ABC, Animal Planet and ESPN) , Ethan Erickson (various commercials), Paula Tiso ( various networks, and commercials)

SAG and aliases

A voice actor may be occasionally credited under an alias. Sometimes producers aren't willing to spend the higher cost of hiring members of the Screen Actors Guild, which prohibits its members from taking non-union jobs; but a voice actor needs income, so he or she may take a job under a false name in an attempt to avoid the SAG's notice. If caught, the SAG may respond with fines and suspended health coverage, so the actor has a motivation to do all he can to discourage people from linking his or her name with the alias. There are several unions that actors may belong to; some notable ones are the American Federation of Television and Radio Artists and Screen Actors Guild in the United States and ACTRA and the Union des Artistes (UDA) in Canada. Some actors prefer to remain non union, or "not affiliated" with any guild or union; a notable example of a strictly non union voiceover agency is Vox Talent.

Training and how-to classes

Instruction in how to enter the voiceovers marketplace and how to market one's services is offered at various acting schools and also at adult learning facilities such as Voices For All or Chicago's Discovery Center.

Many VO coaches who have had success in commercial, narration, and animation offer private training, tele-seminars and weekend workshops for both novice and experienced voice actors. The VoiceOver International Creative Experience (VOICE) in Los Angeles is an annual global conference open to all voice actors, coaches, agents, and producers whose goal is to promote community, education, and technology within the VO industry.

Steady work as a voiceover talent in the US is normally possible only in major metro areas such as New York, Chicago, and Los Angeles, although with the rise of the Internet and digital voice networks (i.e. fiber optic or ISDN lines) that can transmit recordings that voice actors make, this may be slowly changing.

Broadcast schools in the United states taught the basics of traditional radio broadcasting and commercial voice overs, but this called for students to attend in a classroom environment and incur tuition fees totaling thousands of dollars. With the advent of the internet voice acting and voice over courses can take an interactive approach that allows the a person interested in building a career as a voice talent to learn every aspect of the business. The recent Voice Over Success Formula ( ) program is a very good example of the future of voice actor and voice business development via a completely web based, interactive video and multi module seminar program developed by satellite radio executives Michael Mortensen and Ted Kelly.

In Japan

Japanese voice actors (seiyū) work in radio, television and movies. Their work largely mirrors that of their Western counterparts: performing roles in animated cartoons and video games, performing voice-overs for dubs of non-Japanese movies, and providing narration to documentaries and similar programs.

Because the animation industry in Japan is so prolific, seiyū are able to achieve fame on a national level and are able to have full-time careers as voice-over artists. Japanese voice actors are able to take greater charge of their careers than in other countries. Japan also has the institutions to support the career path, with around 130 seiyū schools and troupes of voice actors that work for a specific broadcast company or talent agency. They often attract their own appreciators and fans who watch shows specifically to hear their favorite actor or actress.
Seiyū frequently branch into music, often singing the opening or closing themes of shows in which their character stars, or become involved in non-animated side projects such as audio dramas (involving the same characters in new storylines) or image songs (songs sung in character that are not included in the anime but further develop the character).