The paper provides a comprehensive review of cellulosic bionanocomposites, focusing on their preparation, properties, and applications. Cellulose, the most abundant biomass material, can be extracted from natural fibers to produce nanoscaled fillers such as cellulose nanocrystals (CNCs) and microfibrillated cellulose (MFC). These nanoparticles have gained significant attention due to their potential to enhance the mechanical and barrier properties of biocomposites, making them suitable for industrial packaging. The processing methods for CNCs and MFCs are categorized into hydrosoluble systems, non-hydrosoluble systems, and emulsion systems, each with its own advantages and challenges. The review also discusses the challenges in dispersing CNCs in non-polar media due to their polar surface and the need for surface chemical modifications to improve compatibility with polymer matrices. The mechanical properties of CNCs and MFCs are highlighted, along with their potential applications in various industries. The paper concludes with a detailed overview of the preparation, characterization, properties, and applications of cellulose-based nanocomposites, emphasizing the importance of these materials in the development of high-performance multifunctional composites.The paper provides a comprehensive review of cellulosic bionanocomposites, focusing on their preparation, properties, and applications. Cellulose, the most abundant biomass material, can be extracted from natural fibers to produce nanoscaled fillers such as cellulose nanocrystals (CNCs) and microfibrillated cellulose (MFC). These nanoparticles have gained significant attention due to their potential to enhance the mechanical and barrier properties of biocomposites, making them suitable for industrial packaging. The processing methods for CNCs and MFCs are categorized into hydrosoluble systems, non-hydrosoluble systems, and emulsion systems, each with its own advantages and challenges. The review also discusses the challenges in dispersing CNCs in non-polar media due to their polar surface and the need for surface chemical modifications to improve compatibility with polymer matrices. The mechanical properties of CNCs and MFCs are highlighted, along with their potential applications in various industries. The paper concludes with a detailed overview of the preparation, characterization, properties, and applications of cellulose-based nanocomposites, emphasizing the importance of these materials in the development of high-performance multifunctional composites.