A step outline is a detailed telling of a story intended to be turned into a screenplay for a motion picture.

The step outline details every scene and beat of a screenplay's story, and often has indications for dialog and character interactions. The scenes are often numbered for convenience. It is more detailed and specific than either a treatment or an outline and is generally the last step in the development process before a writer begins writing the screenplay.

It can also be an extremely useful tool for a writer working on a spec script.