A time loop or temporal loop is a plot device in science fiction in which periods of time are repeated and re-experienced by the characters, and there is often some hope of breaking out of the useless cycle of repetition. Sometimes "time loop" is used to refer to a causal loop.
One well-known example of this is in the 1993 film Groundhog Day, in which the main character is the only one aware of the time loop. Stories with time loops commonly center on correcting past mistakes or on getting a character to recognize some key truth; escape from the loop may then follow. The short story "Doubled and Redoubled" by Malcolm Jameson that appeared in the February, 1941 issue of Unknown tells of a person accidentally cursed to repeat a "perfect" day, including a lucky bet, a promotion, a heroically foiled bank robbery, and a successful wedding proposal. This story was a precedent to Groundhog Day and 12:01 PM.
- Butterfly effect
- Eternal return
- Grandfather paradox
- List of films featuring time loops
- List of television series that include time travel
- Time loop logic
- Time travel