O.S.

Heard but Not Seen

The O.S. designation is a crucial piece of formatting used to clarify the source of dialogue. It tells the reader that the speaking character is present in the scene’s location and their voice is part of the scene’s immediate reality (i.e., it is diegetic sound), but the camera is simply not pointed at them at that moment. The character might be in another part of the room, behind a closed door, or speaking from within a crowd.

This technique is used to create a sense of space and realism. It allows a scene to feel larger than the confines of the camera frame and enables a director to focus the audience’s visual attention on one character’s reaction while another character speaks. In a screenplay, the abbreviation is placed in parentheses next to the character’s name in their cue.

Formatting Example: INT. KITCHEN - DAY JANE sips her coffee, staring out the window.

MARK (O.S.) Are you going to be ready in five minutes?

Jane doesn't turn. A small sigh escapes her.

The Crucial Distinction: O.S. vs. V.O.

It is essential not to confuse O.S. (Off-Screen) with V.O. (Voice-Over). The difference is fundamental to the story’s reality:

• O.S. (Off-Screen): The character is inside the scene’s reality, just outside the camera’s view. The other characters in the scene can hear them.
• V.O. (Voice-Over): The character is outside the scene’s reality. Their voice is layered over the scene, and the characters within the scene cannot hear them. This is used for narration or internal monologue.

The full, though less common, term for this effect is Voice Off.