Development hell, also known as development purgatory or development limbo, is media and software industry jargon for a project, concept, or idea that remains in a stage of early development for a long time because of legal, technical, or artistic challenges. A work may move between many sets of artistic leadership, crews, scripts, game engines, or studios. (The related terms production hell and production limbo refer to situations in which a film has begun production but has remained unfinished for a long time without progressing to post-production.)

Some projects enter development hell because they were initially designed with ambitious goals, the difficulty of meeting those goals was underestimated, and attempts to meet those goals have repeatedly failed.

The term is also applied more generally to describe any project that has unexpectedly stalled in the planning or design phase, has failed to meet its originally expected date of completion, and is languishing in those phases for what is seen as an unreasonably long time.^{[citation needed]}

Many projects that enter development hell are gradually abandoned by the involved parties and are never produced.^{[citation needed]}

Film industry companies buy the film rights to many popular novels, video games, and comic books, but often take years to bring those properties to the screen, having first made considerable changes to their plots, characters, and general tone. When this pre-production process takes too long, a project will often be abandoned or cancelled outright. Hollywood starts ten times as many projects as it releases. Less than two percent of all books that are optioned make it to the big screen.

As David Hughes, author of the book Tales From Development Hell (2003), has noted, one reason production is delayed is that, after producers, directors, and actors have been attached to a project, they may request script rewrites. Another cause of delay is that, after people have been attached to a project, they find they have conflicting interpretations of it or visions for it. For example, the director and the studio executives may have different opinions about a film's casting, plot, or budget. Development delays can also result when a lead actor or a key member of the production team withdraws from the project, takes ill, or dies; when there are labor strikes involving the writers, directors, crew, or cast; when there are disputes about intellectual property rights or contract terms; when there is turnover at the studio's executive level and the new leaders have a different vision; or when, due to changes in the wider economic, cultural, or political climate, the film's topic comes to be seen as no longer marketable.

Production hell refers to a situation in which a film has entered production but has remained in that phase for a long time without progressing to post-production.

Television series can experience development hell between seasons, resulting in a long delay from one season to the next. Screenwriter Ken Aguado states that "development hell rarely happens in series television", because writers for a television series "typically only get a few cracks at executing a pilot, and if he or she doesn't deliver, the project will be quickly abandoned."