Pure olive oil is used largely for culinary purposes and in the preservation of foods, particularly canned fish. It is also used in the textile industry for wool combing, in the manufacture of toilet preparations and cosmetics, in the pharmaceutical industry for medicinal purposes, in the manufacture of high-quality castile soap, and as a lubricant.

Olive oil is broadly classified into four grades: (1) extra virgin, oil derived from first pressings that possess excellent taste and odor and has a free fatty acid content, expressed as oleic acid, of not more than 0.8 grams per 100 grams; (2) virgin, oil derived from first pressings that possess good taste and odor and has a free fatty acid content of not more than 2.0 grams per 100 grams; (3) pure, or edible, a mixture of refined and virgin; (4) refined, or commercial, refined lampante. Olive oil is sometimes mixed with other vegetable oils, but this is not legal in all countries; in some countries, it constitutes fraud.