A large body of research data suggests that traditional dietary habits and lifestyle unique to the Mediterranean region (Mediterranean diet, MD) lower the incidence of chronic diseases and improve longevity. These data contrast with troubling statistics in the United States and other high income countries pointing to an increase in the incidence of chronic diseases and the projected explosion in cost of medical care associated with an aging population. In 2013, the MD was inscribed by UNESCO in the “Representative List of the Intangible Cultural Heritage of Humanity.” The 2015–2020 Dietary Guidelines for Americans included the MD as a healthy dietary pattern. Therefore, specific objectives of this article are to provide an overview of the nutritional basis of this healthful diet, its metabolic benefits, and its role in multiple aspects of disease prevention and healthy aging. Whereas recommendations about the MD often focus on specific foods or bioactive compounds, we suggest that the eating pattern as a whole likely contributes to the health promoting effects of the MD.