The Mediterranean diet is a diet inspired by the eating habits and traditional food typical of Crete, much of the rest of Greece, and southern Italy in the early 1960s. This differentiates it from Mediterranean cuisine, which occurs naturally in Mediterranean countries and is inherent to them. While inspired by a specific time and place, the "Mediterranean diet" was later proven and refined based on the results of multiple scientific studies.

The principal aspects of this diet include proportionally high consumption of unprocessed cereals, legumes, olive oil, fruits, and vegetables, and moderate consumption of fish, dairy products (mostly cheese and yogurt), and meat products. Olive oil has been studied as a potential health factor for reducing all-cause mortality and the risk of chronic diseases.

The Mediterranean diet is associated with a reduction in all-cause mortality in observational studies. In 2017, the European Journal of Clinical Nutrition published evidence that the Mediterranean diet lowers the risk of heart disease and early death. The Mediterranean diet may help with weight loss in obese people. The Mediterranean diet is one of three healthy diets recommended in the 2015–2020 Dietary Guidelines for Americans, along with the DASH diet and vegetarian diet. The Mediterranean and DASH diets are two of the main sources for the MIND diet recommendations.

The Mediterranean diet as a nutritional recommendation, that is, as a particular set of foods, is different from the cultural practices that UNESCO listed in 2010 under the heading "Mediterranean diet" on the Representative List of the Intangible Cultural Heritage of Humanity: "a set of skills, knowledge, rituals, symbols and traditions concerning crops, harvesting, fishing, animal husbandry, conservation, processing, cooking, and particularly the sharing and consumption of food".