McDonald's launched the slogan “I'm Lovin' It” worldwide in 2003.
The campaign began in Munich, Germany, in September 2003 and was rolled out internationally afterward. It marked a major shift toward a single global advertising platform, allowing McDonald's markets to share a common phrase, visual identity, and musical theme while adapting executions to local audiences.
The campaign is closely associated with the short “ba da ba ba ba” audio mnemonic. Justin Timberlake appeared in an early campaign music video, and the production involved the advertising agency Heye & Partner. Because music and advertising versions appeared in different markets, people sometimes debate who “wrote” the slogan or song; the branding fact remains that McDonald's introduced the global campaign in 2003.
“I'm Lovin' It” replaced several earlier national slogans rather than merely adding another permanent tagline. It became one of the longest-running central slogans in McDonald's modern marketing.