<p>The corrosion of metals presents a considerable risk to industrial infrastructure, resulting in significant economic and environmental impacts. Recent advancements in the green synthesis of nanoparticles have presented a viable, environmentally friendly method for corrosion mitigation, providing sustainable alternatives to traditional inhibitors and coatings. This review examines recent developments in the synthesis of metallic and metal oxide nanoparticles utilizing biological sources, including plant extracts, bacteria, fungi, and algae. This study systematically analyses the mechanisms of nanoparticle formation, their physicochemical properties, and their interactions with metal surfaces. Their role in passive film formation, barrier protection, and inhibition of electrochemical reactions is emphasized. This paper discusses various characterization techniques employed to assess anticorrosion performance, including electrochemical impedance spectroscopy (EIS), potentiodynamic polarization, and surface analysis. This review emphasizes the comparative performance, long-term stability, environmental safety, and scalability of green-synthesized nanoparticles in relation to their chemically synthesized counterparts. Proposed future research directions aim to connect laboratory successes with real-world applications, emphasizing multifunctional, biodegradable, and cost-effective anticorrosion nanomaterials.</p> Graphical abstract <p></p>