A mockbuster (also known as knockbuster or a drafting opportunity) is a film created to exploit the publicity of another major motion picture with a similar title or subject. Mockbusters are often made with a low budget and quick production to maximize profits. Unlike films produced to capitalize on the popularity of a recent release by adopting similar genre or storytelling elements, mockbusters are generally produced concurrently with upcoming films and released direct-to-video at the same time the film they are inspired by is released. A mockbuster may be similar enough in title and/or packaging that consumers confuse it with the actual film it mimics, but their producers maintain that they are simply offering additional products for consumers who want to watch more films in the same subgenres.

"Mockbuster" is a portmanteau of the words "mock" and "blockbuster".