What advertising slogan did McDonald's begin using in its 2003 global campaign?

McDonald's began using the advertising slogan “I'm Lovin' It” in its 2003 global campaign.

The phrase became a major part of McDonald's international branding and was presented in a deliberately casual, conversational style. The campaign used music, television commercials, print, outdoor advertising, and other media to connect the slogan with everyday enjoyment of the restaurant experience.

The slogan is often confused with earlier McDonald's lines such as “You Deserve a Break Today” and “You, You're the One.” Those campaigns belong to different eras. “I'm Lovin' It” was created for a global campaign and remains one of the company's most recognizable taglines.

The campaign also involved music industry collaborators, including Justin Timberlake and Pharrell Williams. Their involvement sometimes leads people to identify the singer or song rather than the slogan itself, but the canonical branding answer is the five-word phrase.