What was McDonald's original restaurant slogan and operating-system name introduced by the McDonald brothers?

McDonald's original restaurant slogan and operating-system name was the Speedee Service System.

Richard and Maurice McDonald developed the system after redesigning their San Bernardino, California, restaurant in 1948. They reduced the menu, standardized preparation, used assembly-line methods, and focused on serving food quickly. The system helped establish the model later associated with modern fast food.

The name appeared alongside early McDonald's branding and connected the restaurant's promise of speed with its chef mascot, Speedee. It was not simply an advertising tagline: it described the restaurant's distinctive method of production and service.

Readers sometimes confuse it with “Quality, Service and Cleanliness,” a later McDonald's corporate motto, or with the much later “I'm Lovin' It” campaign. Those phrases belong to different periods. Speedee Service System refers specifically to the McDonald brothers' early operating concept and the branding built around it.