A screenwriter or scriptwriter or scenarist is a writer who practices the craft of screenwriting, writing screenplays on which mass media such as films, television programs, comics or video games are based. Screenwriting is a freelance profession. A professional screenwriter must master good storytelling and demonstrate imagination. Screenwriters are not hired employees, they are contracted freelancers. Most, if not all, screenwriters start their careers writing on speculation (spec), meaning they write without being hired or paid for it.

When such a script is sold, it is called a spec script. What separates a professional screenwriter from an amateur screenwriter is that professional screenwriters are usually represented by a talent agency. Also, professional screenwriters do not often work for free, while an amateur will often work for free and are considered writers “in training”. Spec scripts are usually penned by unknown professional screenwriters and amateur screenwriters. There are a legion of would-be screenwriters who attempt to enter the film industry but it often takes years of trial-and-error, failure, and gritty persistence to achieve success.