B movies are low-budget films that the film industry—which had been brought to the brink of economic collapse by the Great Depression during Hollywood’s Golden Age—incorporated into the system to attract more audiences to theaters. B movies emerged as low-budget films—generally lacking in artistic and technical merit—that were shown in theaters following the A movies, which were the main films intended to reach the audience.

"B movie" is the term used to refer to films shown after those classified as "A movies," listed in alphabetical order. It is often mistakenly believed that B movies are named after the first letter of the word "bad" because they are low-budget and lack professionalism.

The Great Depression, which began in the United States in 1929, negatively affected the film industry, just as it did all other sectors. As the costs of film production and exhibition rose, economically strained moviegoers began going to the movies less often in an effort to save money. To stem the decline, movie theaters in New England began showing two films back-to-back (double features) for the price of a single ticket. This approach made movie tickets seem like a better value in an environment of economic contraction. The solution worked, and attendance increased. Within a short time, the “two-for-one” practice began to spread across the country in various forms.

Despite the widespread adoption of the “two-for-one” system, screening two high-level films—particularly for theaters affiliated with major film studios—unexpectedly drove up costs. To address this issue, major movie theaters first opted to screen a top-tier film—classified as an “A” film—followed by a low-cost film—classified as a “B” film. During the release period, “B” films began to be categorized based on cost, runtime, and quality:

“Major studio B films” produced by the so-called “Big Five”—MGM, Paramount, Warner Bros., Twentieth Century Fox, and RKO.

"Major-studio programmers" are B-movies that could be screened as either A or B films depending on the theater’s programming needs.

“Smaller company Bs” produced primarily by companies such as Monogram, Republic, and Producers Releasing Corporation (PRC).

Very low-budget B-movies produced by small production companies in Hollywood from the 1920s to the 1950s, known as “Poverty Row.” There were generally significant differences in artistic and technical quality among these financially distinct types of B-movies. For example, major studio programmer films were far superior to smaller company B movies in both technical and artistic terms. The double-feature screening method yielded positive results for audiences, movie theaters, industry workers, and film producers amid an economic downturn. Moviegoers gained the advantage of watching two films—one of type A and one of type B—with a single ticket. This was significant not only as a simple financial benefit but also in terms of mitigating the psychological effects of the economic collapse on individuals. B movies, in particular, were capable of completely transporting the audience away from the economic collapse they were experiencing.

Movie theaters increased ticket sales at very low cost and boosted their profitability by scheduling low-cost B movies immediately after high-cost, low-attendance A movies. B movies, which emerged during the Great Depression for economic reasons, quickly became a testing ground for every component of the film industry—from producers to audiences. Despite their low production costs, B movies continued to be produced after the Great Depression due to the profits they generated. This aspect of cinema—accessible to nearly everyone and widely accepted—played a crucial role in the development of cinema not only in the United States but around the world. Unlike mainstream films, B movies around the world constantly pushed boundaries by taking significant risks and creating a shock effect to draw audiences into theaters. Filmed in this manner, B movies created a vital space for the emergence of many cult, absurd, banned, and independent films. Alongside cult, absurd, banned, and independent films, the exploitation film genre—which challenges legal, moral, and social boundaries on topics such as sex, nudity, race, social class, violence, and many others—also expanded under the umbrella of B movies. Just as risks were taken in terms of technique and content, certain risks were also taken with the cast and crew. B-movies became an easy first step for launching a film career. Many people who began their careers in B-movies gained the experience necessary to continue their careers in A-movies and, later, on television.

Until the 1950s, B-movies were generally shown in theaters, but with the spread of television, they began to find their way into homes as well. Films classified as “midnight movies” frequently featured B-movies. B-movies served as an important launching pad for independent cinema and exploitation cinema. The content of these films could be provocative. Due to fluctuating censorship restrictions and financial constraints, B-movies—which fell outside the mainstream—gradually found their place in various screening venues over time. Drive-ins and grindhouses were important venues and revenue sources for B-movies. With the widespread adoption of VHS and, later, the internet, B-movies reached their widest distribution channel in history. With P2P technology, the audience base began to solidify in the late 20th century. Magazines, blogs, websites, and festivals dedicated to B-movies helped them gain partial acceptance even among mainstream audiences over time.

A common misconception about B movies is the belief that they are all “bad.” It is often assumed that the abbreviation “B” comes from the word “bad.” While there are indeed many films in this category that could be described as bad, there are also numerous B movies that have achieved cult status or become classics. B movies are low-budget productions. For this reason, cost-cutting measures are taken across multiple aspects of the film. Art direction, costumes, makeup, technical crew, visual effects, cinematography, and all other disciplines are at risk due to the limited budget. Issues that distinctly give the film its "B-movie" flavor are immediately noticeable. These issues are accepted by audiences as part of the B-movie’s character. Over time, the B-movie evolved from its origins in Hollywood’s Golden Age into a distinct film genre and spread worldwide. Recurring critical errors in low-budget films have led to their classification as “B-movies” worldwide. Most B-movies attempt to overcome problems stemming from a lack of funding through bold storytelling in their screenplays. In this way, despite their low budgets, topics that typically require substantial funding, extensive research, and technical, artistic, and acting skills are tackled boldly: interplanetary wars, giant creatures invading cities, and so on.