Quiz Holdings, LLC, doing business as Quiznos, is an American franchised fast-food restaurant based in Denver that specializes in offering toasted submarine sandwiches. It was founded in 1981 by Jimmy Lambatos and sold to Rick and Richard Schaden ten years later. It then grew to nearly 5,000 restaurants; by 2013, Quiznos was the second-largest submarine sandwich shop chain in North America, behind Subway. It filed for bankruptcy in 2014; by 2016, it had dropped to ninth place, and the number of Quiznos locations in the United States fell from a 2007 high of 4,700 to just 400 a decade later.

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.