Deep eutectic solvents (DESs) have been established as an emerging green alternative solvent media for the sustainable valorization of biomass. DES offers advantages over conventional organic solvents, and it is usually prepared by mixing the hydrogen bond acceptor (HBA) and hydrogen bond donor (HBD). DES exhibits exceptional properties over conventional organic solvents, such as tunability, biodegradability, recyclability, and low toxicity. The growing exploitation of DES in biomass valorization makes it an emerging medium for sustainability advantages. The sustainability advantages of biomass valorization include enhanced productivity and product quality, biodegradability, recyclability, reduced energy consumption, and reduced environmental impacts. DESs serve as an emerging sustainable media for processing operations such as extraction, purification, separation, catalysis, conversion, and enzymatic hydrolysis. DESs efficiently break the complex chemical structure of biomass and can dissolve and extract the valuable bioactive compounds from biomass. This process subsequently improves the extraction, purification, and separation for sustainable biomass valorization. Apart from their advantages, some challenges remain with the exploitation of DESs, and these challenges can be addressed by other sustainable technologies or biorefinery concepts. The distinctive properties and versatility of DESs make them a fascinating choice for biomass valorization and their sustainability.