Passive daytime radiative cooling (PDRC) is emerging as a promising low-energy strategy for reducing solar heat gain, moderating surface temperature, and lowering cooling demand in buildings and outdoor environments. Among the available material platforms, cellulose-derived systems are attracting growing attention because they combine renewable feedstocks, water-compatible processing, porous light-scattering architectures, and favourable mid-infrared vibrational activity. This critical literature review examines cellulose-derived PDRC materials reported from 2019 to 2025, with emphasis on structure–property relationships, optical and thermal performance, durability under climate-relevant stressors, and relevance to sustainable cooling applications. The analysis covers films, foams, aerogels, transparent wood-based systems, textiles, and hybrid composites, and highlights how composition, pore morphology, surface chemistry, and hybridisation strategies influence solar reflectance, thermal emissivity, cooling capability, and application-specific functionality. The reviewed literature shows a clear transition from proof-of-concept cooling materials towards increasingly robust and multifunctional systems. However, major barriers remain, including inconsistent reporting of performance metrics, limited long-term outdoor validation, insufficient durability benchmarking, and weak linkage between laboratory-scale measurements and realistic cooling-use conditions. Overall, cellulose-derived materials represent a promising bio-based platform for sustainable cooling technologies.