As international relations expand from nation-states to include more nonstate actors, and communication and commerce erase national borders, culture becomes the new frontier for defining identities as well as allegiances. Culture is integral to communication between nations and foreign publics. Cultural diversity is also a defining feature of the global communication era. This chapter contrasts the wave of interest in culture that spread across international relations studies, with the relative narrow view of public diplomacy on culture as a tool, product, or vehicle for communication. Missing is the role of culture as a force that shapes and defines a nation’s communication. U.S. public diplomacy appears to have its distinct style of communicating. This chapter explores some of the cultural features of U.S. public diplomacy and concludes with ways U.S. public diplomacy can develop a multicultural approach to help guard against unintended identity challenges with culturally diverse publics.