Olive oil is an oil extracted from the fruit of the olive tree. It is the only vegetable oil that can be created simply by pressing the raw material. It is used in cooking and cosmetics, and regarded as healthful dietary oil because of its high content of monounsaturated fat.

The standards of olive oil quality are set by the International Olive Oil Council (IOOC) based in Madrid, Spain.

In the United States the olive oil standards and terminology are set by the United States Department of Agriculture.

The best quality olive oil is the extra-virgin olive oil obtained from the first pressing of the olives solely by mechanical or other physical means.

Olive oil is ideal for frying. Its high smoking point (210ºC) is substantially higher than the ideal temperature for frying food (180ºC), and without over-heating it undergoes no substantial structural changes and keeps its nutritional value better than other oils.

Another advantage of using olive oil for frying is that it forms a crust on the surface of the food that impedes the penetration of oil and improves its flavour. In addition, olive oil goes further than other oils, and not only can it be re-used more often than others, but also increases in volume when reheated, so less is required for cooking and frying.

44% of world olive oil is produced in Spain. Spain is followed by Italy and Greece. According to National Geographic News, olive oil, once considered an "ethnic food" in the U.S., experienced rapid popularity growth in the 1980s. Today the U.S. imports more than 50 million gallons (189 million liters) a year.