Subcompact car is a North American term used to describe automobiles whose class size is smaller than that of a compact car, usually not exceeding 165 inches (4,191 mm) in length, but larger than a microcar. According to the United States Environmental Protection Agency (EPA), a passenger car is classified as subcompact if it has between 85 cubic feet (2,407 L) and 99 cu ft (2,803 L) of interior volume.

In North America, the term "subcompact" came into popular use in the early 1970s. Previously, cars in this size were variously categorized, including "small automobile" and "economy car." This type of car has been around since the 1940s with the Crosley, and in the 1950s with the captive import, the Nash Metropolitan. A number of imported models, notably the Volkswagen Beetle and various small British cars, were also marketed at "economy" cars during this time.

The subcompact market segment expanded in the 1970s with the introduction of new domestic-built models produced by North American automakers in response to the growing popularity of small imported cars from Europe and Japan.

The AMC Gremlin was described at its April 1970 introduction as "the first American-built import" and the first U.S. built subcompact car. The Chevrolet Vega and Ford Pinto subcompacts were introduced in September 1970 for the 1971 model year.

The Pontiac Astre, the Canadian-born re-badged Vega variant was released in the U.S. September 1974. The Vega-based Chevrolet Monza and the Pinto-based Ford Mustang II were upscale subcompacts also introduced for the 1975 model year as larger pony cars the Chevrolet Camaro and Ford Mustang sales had fallen. The Camaro was scheduled for cancellation, but sales stabilized with the end of the gas crisis. The Monza with its GM variants Pontiac Sunbird, Buick Skyhawk, and Oldsmobile Starfire, and the Mustang II continued until the end of the decade. The Chevrolet Chevette was GM's new entry-level subcompact introduced as a 1976 model. It was an 'Americanized' design from Opel, GM's German subsidiary. The front-wheel drive (FWD), U.S.-built Ford Escort and Mercury Lynx subcompacts were introduced as 1981 models replacing the Ford Pinto and Mecury Bobcat.

Captive imports was the other response by U.S. car makers to the increase in popularity of imported subcompact cars in the 1970s and 1980s. These were cars bought from overseas subsidiaries or from companies in which they held a significant shareholding. GM, Ford, and Chrysler sold imports for the U.S. market. The Buick Opel, Ford Cortina, Mercury Capri, Ford Festiva, and Dodge Colt are examples.