Diet Coke debuted in the United States in 1982 as Coca-Cola’s first cola developed specifically under the Coca-Cola name without sugar.
The launch responded to growing demand for reduced-calorie soft drinks. Coca-Cola had already marketed Tab, introduced in 1963, but Diet Coke was positioned as a direct extension of the company’s best-known trademark rather than as a separate independent brand.
Diet Coke quickly became a major global soft-drink brand. Its packaging, advertising, and name connected it visibly to Coca-Cola while distinguishing it from the original sugar-sweetened drink. The product’s launch also established a long-running low-calorie cola line that later included additional formulations and variants.
Diet Coke is sometimes confused with Coca-Cola Zero, which arrived much later, in 2005. Tab is also not the correct answer: it predates Diet Coke and was marketed under its own brand name.