In the last few years, the production of olive oil has incredibly increased due to its beneficial properties on human health. On the other hand, the amount of waste and by-products derived from the olive oil industry has increased as well, prompting the development of new fields of research aiming to reduce disposal costs and valorize bioactive compounds from the viewpoint of the green economy. Interestingly, olive oil and by-products contain numerous molecules, including phenols, exhibiting pleiotropic effects in both in vitro and in vivo studies. This review aims to describe the more recent studies focusing to identify and describe the potential roles and the new applications of extracts isolated from wastes and by-products or specific compounds, such as hydroxytyrosol (HT) and oleuropein. Extracts or bioactive molecules from olive oil and by-products have been proposed as a food additive, to produce biofuel, for animal feeding, and to create new matrices in bioremediation protocols. Moreover, bio-compounds have been described to have numerous beneficial effects on human health as they reduce the risk of developing certain chronic diseases. Despite the already published studies, more research is necessary to valorize bioactive compounds in olive oil and by-products, as well as their potential use to improve human health and green applications in different industrial processes. Keywords: extra virgin olive oil, by-products, olive leaf extract, bioactive compounds, human health, and industrial application