A sub-series is simply a series that is entirely part of another series. If every entry in series B is also an entry in series A but the reverse is NOT true (i.e. series A also contains many entries that are not part of series B), then series B is a sub-series.
- The Videssoos series by Harry Turtledove includes the Tale of Krispos and Time of Troubles subseries and a sub-series called The Videssos Cycle
- The Hunky and Spunky sub-series is part of the Color Classics series.
- Pixar's Toy Story 'Toons and Cars 'Toons a.k.a Mater's Tall Tales are sub-series of the ''Toy Story and Cars series respectively.
- The Three Little Pigs shorts are a sub-series within the Silly Symphonies series.