may refer to:
- Fault (geology), planar rock fractures which show evidence of relative movement
- Fault (technology), an abnormal condition or defect at the component, equipment, or sub-system level which may lead to a failure
- An asymmetric fault or symmetric fault in an electric power system
- Fault (dog), in animal breeding, is a conformation point whose state or quality falls outside of the acceptable range for the attribute being judged
- In tennis, a "fault" could be either a foot fault or a service fault, where an aspect of the server's serve is not in line with the rules of the game
- Fault (legal), in criminal law, one must determine fault in a crime.
- Fault (electrical), an unintended electrical connection commonly referred to as a "short circuit".