Closed captioning is the process of displaying text on a television, video screen or other visual display to provide additional or interpretive information to individuals who wish to access it. Closed captions typically show a transcription of the audio portion of a program as it occurs (either verbatim or in edited form), sometimes including non-speech elements.

The term "closed" in closed captioning indicates that not all viewers see the captions—only those who choose to decode or activate them. This distinguishes from "open captions" (sometimes called "burned-in" or "hardcoded" captions), which are visible to all viewers.

Most of the world does not distinguish captions from subtitles. In the United States and Canada, these terms do have different meanings, however: "subtitles" assume the viewer can hear but cannot understand the language or accent, or the speech is not entirely clear, so they only transcribe dialogue and some on-screen text. "Captions" aim to describe to the deaf and hard of hearing all significant audio content—spoken dialogue and non-speech information such as the identity of speakers and, occasionally, their manner of speaking—along with music or sound effects using words or symbols.