Deep eutectic solvents (DESs) have emerged as a sustainable alternative to conventional solvents in extraction and separation processes due to their low volatility, tunable solubility, ease of preparation, low cost, and environmental compatibility, making them highly suitable for diverse applications. DESs are used in extraction either by using a preprepared DES to selectively dissolve or absorb specific compounds or by forming a DES in situ through the addition of a hydrogen bond acceptor (HBA) to a mixture containing hydrogen bond donors (HBDs). This chapter discusses the role of DESs in various extraction techniques, such as liquid–liquid and solid–liquid extraction, and in separating valuable compounds from complex matrices. It highlights recent advancements, like using DESs to extract bioactive materials from natural products, recover metal from industrial waste, and remove organic contaminants from the environment. The chapter also delves into the mechanisms behind DES-based extraction, explaining solute–solvent interactions and how DESs enhance the extraction effectiveness. Finally, it explores future research directions, emphasizing the continued development of DES formulations, their mechanisms, and their integration into sustainable extraction technologies. As research progresses, DESs are poised to play a key role in advancing sustainable extraction and separation processes in industrial practices.