The Filet-O-Fish, introduced in 1963, became one of McDonald’s early nationally marketed product brands.
Franchisee Lou Groen developed the sandwich in Cincinnati, where many customers observed meatless eating practices on Fridays. The fish sandwich gave McDonald’s a way to serve that local demand while expanding the menu beyond hamburgers and cheeseburgers.
The Filet-O-Fish was first tested locally before being added to the national menu. Its name combined a fish reference with McDonald’s “Filet-O” naming style, making it easy to identify as a branded McDonald’s product.
The sandwich is sometimes dated only to its later national expansion, but 1963 is the key year associated with its introduction. Its long survival also makes it one of the company’s most enduring menu names.