Polyvinyl alcohol (PVA) and nanocellulose (NC) composite systems are promising candidates with exciting implications for sustainability, adaptability, and future uses. This research investigates the synergistic features of PVA and nanocellulose, focusing on their renewable and biodegradable nature as important contributors to sustainable material development. An overview of various processing techniques of PVA/NC composites, and their morphological, thermo-mechanical, barrier and biodegradable properties is examined, revealing its enhanced performance attributes compared to conventional materials. This review also discusses the numerous applications of PVA and nanocellulose composites in packaging, biomedical engineering, and environmental remediation. Furthermore, the discussion expands on the potential future applications of these composites, emphasizing their importance in tackling critical global concerns such as pollution reduction, resource conservation, and healthcare breakthroughs. With ongoing research focusing on functionalisation strategies and scalable production methods, PVA and nanocellulose composites are poised to revolutionize multiple sectors, offering sustainable solutions that align with the principles of circular economy and environmental stewardship. Finally, this review emphasises the enormous contributions of PVA and nanocellulose composites to sustainable material innovation, their broad applicability across industries, and their promise to shape a more resilient and environmentally friendly future.