A fast-food restaurant, also known as a quick-service restaurant (QSR) within the industry, is a specific type of restaurant that serves fast-food cuisine and has minimal table service. The food served in fast-food restaurants is typically part of a "meat-sweet diet", offered from a limited menu, cooked in bulk in advance and kept hot, finished and packaged to order, and usually available for take away, though seating may be provided. Fast-food restaurants are typically part of a restaurant chain or franchise operation that provides standardized ingredients and/or partially prepared foods and supplies to each restaurant through controlled supply channels. The term "fast food" was recognized in a dictionary by Merriam–Webster in 1951.

Arguably, fast-food restaurants originated in the United States with White Castle in 1921. Today, American-founded fast-food chains such as McDonald's (est. 1940) and KFC (est. 1952) are multinational corporations with outlets across the globe.

Variations on the fast-food restaurant concept include fast-casual restaurants and catering trucks. Fast-casual restaurants have higher sit-in ratios, offering a hybrid between counter-service typical at fast-food restaurants and a traditional table service restaurant. Catering trucks (also called food trucks) often park just outside worksites and are popular with factory workers.