A spin-off is a series that takes place in the same universe as Inspector Spacetime and usually borrows some characters from it. Because of the original show's long run, it has produced several spin-offs.
- FE-Line and Friends (1980)
- Peacemist: Nicer Post (2005–2010)
- The Mary Sue Predicaments (2006–2011)
- FE-Line (2008–2013)
- Break (2015)
- EXO-POL (2023–)
