The exponential advancement of science and technology, especially within the realm of nanotechnology, has significantly expanded the applications of metal and metal oxide nanoparticles across various industrial sectors, scientific domains, and research institutions. Nickel oxide nanoparticles, in particular, have garnered considerable interest due to their unique characteristics and versatile applications. This paper comprehensively reviews NiO NPs, emphasizing their biological synthesis methods, characterization techniques, and wide‐ranging biomedical applications. These applications include their efficacy against fungal, bacterial, and viral infections, anticancer properties, and potential as innovative therapeutic agents for numerous diseases. Our findings underscore the novelty of NiO NPs in enhancing therapeutic strategies and expanding their biomedical applications, paving the way for innovative medical interventions.The objective of this review is to elucidate a thorough overview of the current research landscape, highlight recent developments, and explore the potential future directions for NiO NPs.