The underscore _ is a typographic element.
Underscore, underline or _ may also refer to:
- Macron below, a diacritic accent
- Underscore (dance), a practice in contact improvisation developed by Nancy Stark Smith
- Underscore Records Pvt. Ltd., an Indian record label
- Underscore.js, a JavaScript library providing utility functions for common programming tasks
- Underscoring, a technique in musical theatre
- _ (album), a 2016 album by BT
- Underscores (musician), an American musical artist