A script breakdown is an intermediate step in the production of a play, film, comic book, or any other work that is originally planned using a script.

In theatre, it is a general term for identifying possible dividing points within the play, to organize the work of the playwright, actors, director, or other creative personnel. A dramaturg may use script breakdowns to guide the work of a playwright.

In film and television, it is a summary of a screenplay or teleplay. Screenwriters usually create breakdowns before the screenplay is written; many screenwriters believe that effective screenplays share certain structural elements, and that breakdowns should therefore always include these elements. Later, directors and editors create breakdowns from the script, to organize the process of shooting and editing the film.

In comic books, it is the process of determining how each action, character, and piece of dialogue described in the script will be placed visually on a page. In the studio system that dominated mass-market comic-book production from the 1940s through the 1970s, breakdowns were done by the penciller or by a separate breakdown artist, rarely by the scriptwriter; in some cases, breakdowns were done from a rough story outline before the dialogue was written. Later comics writers such as Alan Moore and Neil Gaiman, influenced by cinematic technique, began to include more layout details within their scripts. Cartoonists who both write and draw their own work sometimes begin with a script and do their own breakdowns, and sometimes work through drawings without a separate script.