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. An individual who performs such voice-only roles is known as a voice actor or actress or as a voice artist. Voice acting 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 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.

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's vocal cords became strained during the recording of the Lion King, Jim Cummings was called in to finish the recording.

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.

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. Another voice actress who would fit this criterion is Veronica Taylor, who for several seasons voiced Ash Ketchum in the North American version of the Pokémon anime. 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 an adolescent male actor would change over time, the voice of an adult female will not.