Phenolic compounds are abundant in nature and have multiple beneficial effects on human health due to their antioxidant, anti-inflammatory, antithrombotic, antiallergenic, anticancer, and antiatherosclerotic properties. For this reason, phenolics are becoming relevant functional ingredients for several industries, mainly the food industry, derived from food consumer exigencies and regulations. However, the use of their beneficial properties still presents some limitations, such as chemical instability under environmental and processing conditions, which leads to structural changes and compromises their biological activities. They also present poor water solubility and sensitivity to pH changes, decreasing their bioavailability in the organism. The technologies for extraction and stabilization of these compounds have evolved rapidly in the development of different delivery systems to encapsulate sensitive active molecules. Biopolymeric nanoparticles are biodegradable polymer-based colloidal systems with sizes ranging from 1 to 1000 nm, and different techniques can be carried out to develop them. These systems have emerged as a green and effective alternative to improve stability, bioavailability, and biological effects of phenolic compounds. This comprehensive review aims to present an overview of recent advances in encapsulation processes of phenolic compounds within biopolymer nanoparticles as delivery systems and the impact on their physicochemical properties and biological effects after encapsulation.