Lycium barbarum L. is a species widely used in dietary supplements and natural healthcare products. The berries, also known as goji or wolfberries, mostly grow in China, but recent reports on their outstanding bioactive properties have increased their popularity and cultivation around the world. Goji berries are a remarkable source of phenolic compounds (such as phenolic acids and flavonoids), carotenoids, organic acids, carbohydrates (fructose and glucose), and vitamins (ascorbic acid). Several biological activities, such as antioxidant, antimicrobial, anti-inflammatory, prebiotic, and anticancer activities, have been associated with its consumption. Hence, goji berries were highlighted as an excellent source of functional ingredients with promising applications in food and nutraceutical fields. This review aims to summarize the phytochemical composition and biological activities, along with various industrial applications, of L. barbarum berries. Simultaneously, the valorization of goji berries by-products, with its associated economic advantages, will be emphasized and explored.