Filet-O-Fish was McDonald’s first major signature sandwich, introduced in 1963.
Franchisee Lou Groen developed the sandwich in Cincinnati, where many customers observed meat-free religious eating practices on Fridays. McDonald’s needed a menu item that could attract those customers without abandoning its fast-service format. The fish sandwich provided a branded alternative to the company’s beef-centered menu.
The Filet-O-Fish was introduced before the Big Mac and became one of McDonald’s most enduring named products. Its branding relied on a distinctive name, a fish fillet, cheese, and tartar sauce, making it easy to identify alongside the company’s burgers.
A common mix-up is treating the sandwich as a modern menu innovation because it remains available today. In fact, its 1963 launch places it among McDonald’s earliest signature products. The recipe and fish sourcing have changed in different periods and markets, but the Filet-O-Fish name has remained part of McDonald’s brand history.