V.O. vs. O.S. in a Screenplay: How to Write Voice-Over and Off-Screen Dialogue

(V.O.) and (O.S.) are two small extensions that sit next to a character name, and they're easy to mix up. This guide explains exactly what each one means, when to use it, and how to format it, from narration and inner thoughts to phone voices and a character shouting from the next room. You'll also see where practice varies and the mistakes that make a script look amateur.

Updated September 2026 · 8 min read

1. The difference in one sentence

O.S. (off-screen) means the character is physically in the scene, just not in the camera's view. V.O. (voice-over) means the voice is not physically in the scene at all: a narrator, a character's thoughts, a voice on a phone or a recording.

The test is simple. Ask yourself: could the other characters in this scene hear this voice in the room? If yes, and the speaker is just out of frame, it's O.S. If the voice comes from somewhere else in time or space, it's V.O.

2. How to format the extension

The extension goes on the same line as the character name, after a space, in capital letters and inside parentheses. It's part of the character cue, so it sits in the same centered-left position as the name.

A few formatting points most writers follow:

• Keep the periods: (V.O.) and (O.S.), not (VO) or (OS). Some writers drop them, but the dotted form is the standard.
• Use the character's normal name. SARAH (V.O.), not NARRATOR SARAH or OLD SARAH, unless the older version is genuinely a separate character in your script.
• Don't put the extension in a parenthetical below the name. (V.O.) belongs next to the name; a parenthetical is for how a line is delivered.
• The dialogue under it is formatted exactly like any other dialogue.

If you need a refresher on character cues, dialogue and parentheticals, see the full screenplay format guide.

3. When to use V.O.

Narration

A narrator speaks over the images, usually from a point outside the story's present moment. The narrator can be a character in the film, often an older version looking back, or someone who never appears on screen.

Inner thoughts

When we hear what a character is thinking while we watch them, that's V.O. Their lips don't move; the voice exists only for the audience.

Phone voices, recordings and devices

A caller we hear but don't see, a voicemail, a radio broadcast, a voice on a video someone is watching: the speaker is not in the room, so most writers use V.O. Some prefer more specific extensions such as (ON PHONE), (FILTERED), (ON TV) or (ON RADIO). All are accepted; pick one per situation and stay consistent. Phone calls have their own options, including intercutting, covered in how to write phone calls and texts.

Letters, diaries and messages read aloud

When we see a character reading a letter and hear the writer's voice, the writer speaks in V.O. The same goes for a diary entry heard over images.

Voices from another time

A line from an earlier scene echoing in a character's memory is also V.O., since the speaker isn't there now. If you show the memory itself on screen, that becomes a flashback, and the dialogue inside it is normal dialogue.

4. When to use O.S. (and O.C.)

Use O.S. when the character is physically part of the scene but the camera isn't on them. The other characters can hear them, and often answer.

Typical O.S. situations:

• A character calling from another room, upstairs, or behind a closed door.
• Someone speaking before they enter the frame, such as a voice from the doorway before we see who it is.
• A character in the same room who is simply not in the current shot. Many writers skip the extension here, because in a spec script you're not directing the camera; use it only when the fact that we can't see them matters.

O.C. (off-camera) means the same thing as O.S. You'll mostly see it in some multi-camera TV scripts and older screenplays. For a feature spec, O.S. is the common choice. Whichever you use, don't mix both in one script.

5. Narration across scenes

Narration often carries over several scenes or a whole sequence while the images change. There are two common ways to handle this, and both are accepted.

Option 1: split the narration at each scene heading

Write each new scene heading and its action, then continue the narrator's dialogue under a new (V.O.) cue. This is the clearest method for readers and the most common.

Option 2: one block of narration over a sequence

For quick images under one continuous speech, some writers use a montage or series of shots and place the narration before or after it, sometimes with an action line such as Over this, we hear Sarah. This keeps a long speech in one piece, but make sure the reader can still tell which image goes with which line.

Whichever you choose, the narrator's name stays exactly the same from the first page to the last.

6. CONT'D with V.O. and O.S.

(CONT'D) marks that the same character keeps speaking after an interruption, usually an action line. When the cue already has an extension, the two sit side by side: the extension first, then (CONT'D).

Practice varies here. Many writers now leave out (CONT'D) within a scene entirely, and most screenwriting software lets you switch it on or off. What matters is consistency: either use it everywhere the rule applies or nowhere.

If a character moves from O.S. to on screen, drop the extension on the first line after they appear. MARK (O.S.) becomes simply MARK once he walks into the bathroom.

7. Common mistakes

• Using O.S. for narration or thoughts. A narrator isn't hiding behind a door. If the voice isn't physically in the scene, it's V.O.
• Using V.O. for a character in the next room. They're in the scene and the others can hear them, so it's O.S.
• Narration that describes the picture. "I walked into the kitchen and saw my mother crying" over a shot of exactly that tells the reader nothing new. Good voice-over adds what the images can't: irony, context, a feeling the character hides, a view from years later.
• Using narration to explain the plot. If you need a voice to explain what's going on, the scenes probably aren't doing their job. Narration works best as a deliberate style choice, not a repair.
• Inconsistent extensions. (V.O.) on one call, (ON PHONE) on the next, (O.C.) on page 40 and (O.S.) on page 60. Pick a system and stick to it.
• Extensions in the action line. Write MARK (O.S.) in the character cue, not Mark says off-screen in the action.

Before you send a draft out, a quick pass with the screenplay format checker helps catch inconsistent cues.

8. Frequently asked questions