Which slogan has been McDonald's global advertising tagline since 2003?

“I'm Lovin' It” has been McDonald's global advertising tagline since 2003.

McDonald's launched the campaign in 2003, using the phrase in advertising and pairing it with the distinctive “ba da ba ba ba” musical signature. The campaign was designed for international use and became one of the company's most recognizable branding elements.

The phrase is often associated with the singer Justin Timberlake because he appeared in an early campaign advertisement and recorded a related song. The slogan itself, however, is McDonald's advertising property rather than the title of a Timberlake album.

It also followed earlier McDonald's campaigns such as “You Deserve a Break Today.” Those older slogans remain important in advertising history, but “I'm Lovin' It” is the long-running global tagline introduced in the early 2000s.