The North American Olive Oil Association's website includes an Olive Oil Guide and extensive information about the uses, health benefits, types, production, and sustainability of olive oil.

The Olive Wellness Institute's Extra Virgin Olive Oil Health and Nutrition Report offers a wealth of evidence-based information to consumers, answering many of the most common questions about olive oil, its use, and its health benefits.

Olive News Press Review provides introductions from and links to the latest news articles from around the world "focused on the international olive oil sector and related subjects such as the Mediterranean Diet, health, etc." It is curated by the International Olive Council.

The International Olive Council Glossary of Terms (with many useful definitions).

The National Bank of Greece’s May 2015 Sectoral Report, “Olive Oil: Establishing the Greek brand,” provides extensive information about the Greek olive oil world, including statistics.

How to Buy Great Olive Oil, from Extra Virginity author Tom Mueller’s website, Truth in Olive Oil, which is focused on “advising consumers about buying and enjoying oil, connecting them with skilled oil-makers, celebrating the culture of this storied substance, and calling out fraudulent oils which cheat consumers and undercut honest producers.” 

5 Foolproof Tips for Buying Good-Quality Olive Oil provides some of the best expert advice available, concisely presented.

What Is the Healthiest Olive Oil? actually goes well beyond that question to discuss the various types of olive oil available in the USA and where and how to buy them.

Oldways offers a wealth of recipes, tips, and information about the Mediterranean Diet (as well as other traditional diets), plus links to abstracts of relevant studies on the health benefits of eating well.

Slick Extra Virgin offers useful explanations of various aspects of the chemical analysis of extra virgin olive oil.

The UC Davis Olive Center website provides useful information for olive growers, processors, consumers, and buyers, including news related to olive oil and research reports about scientific studies.

Olive Oil Appreciation is just one of many highly informative sections on Alexandra Kicenik Devarenne's CalAthena website. This page provides an introduction to olive oil tasting and explains how to recognize rancidity; the blog features dozens of articles on a variety of topics.

Extra Virgin Olive Oil: Complex, Compelling, and Commercial is a very brief guide for olive oil buyers without extensive training in olive oil evaluation.