The Filet-O-Fish was introduced by McDonald’s in 1963 to appeal to Catholic customers during Lent.
Franchisee Lou Groen developed the fish sandwich in Cincinnati, where many customers observed the Catholic practice of avoiding meat on Fridays during Lent. The item gave McDonald’s a non-meat alternative while preserving the restaurant’s quick-service format.
The sandwich became a permanent menu item rather than a seasonal experiment. Its core components have included a breaded fish fillet, a bun, tartar sauce, and cheese, although regional versions and fish species have varied.
The Filet-O-Fish is sometimes incorrectly described as McDonald’s first fish product worldwide or as a product created at corporate headquarters. Its origin is specifically tied to Groen’s Cincinnati franchise and the local business problem he was trying to solve.