This book comprehensively reviews the phytochemistry, functional properties, and health-promoting effects of bioactive compounds found in oil processing by-products, and it also explores the food and non-food applications of these by-products. Several oilseeds, vegetables, and fruits are cultivated for their oils and fats, wherein the oil extraction industry generates a huge amount of waste (meal or cake). The valorisation of this waste would be very beneficial not only from the economic and environmental perspectives, but also for the potential applications in food, cosmetics and pharmaceutical industries, in which phytochemicals derived from vegetable oil and oilseed processing by-products play an important role in, for instance, extending the shelf life of several products and providing added-value properties with their antioxidant and antimicrobial properties. In this work, expert contributors discuss about the added-value of biowaste from common and non-traditional vegetable oils and oilseeds processing, as well as fruit oils processing, and offer an extensive overview of the different bioactive compounds found in extracts from oil processing by-products and their chemical composition. The book also collects several examples in which oil processing by-products are integrated into industrial activities such as food production, livestock production and in pharmaceutical and cosmetics industries. Professionals and scholars alike interested in the recycling of agro-industrial wastes derived from vegetable oil and oilseed processing by-products will find this book a handy reference tool.