Nightside may refer to:
- "Nightside with Dan Rea", which is a non-syndicated talk radio show hosted by Dan Rea and running on WBZ 1030, the oldest surviving commercial radio station in New England. Nightside runs from 8 to Midnight on weeknights.
- The Canadian late-night radio talk show The Nightside, hosted by Mark Elliot
- NBC Nightside, NBC's now-defunct late night news program, comparable to ABC's World News Now and CBS' Up to the Minute.
- Nightside (book series), a series of fantasy-noir novels by author Simon Green
- Nightside, a fictional character in the Marvel Universe, is a member of the Shi'ar Imperial Guard.
- Nightside is also a comic-book miniseries published in 2001-2002 by Marvel comics and Robert Weinberg.
- nightside or night side, that portion of the Earth, other planetary body, or moon characterized by darkness that faces away and opposite to the direction of sunlight/starlight defined by the terminator (solar) line.