Nanotoxicology is a branch of toxicology focused on studying the effects of nanomaterials (NMs) on human health and the environment. As nanomaterials are increasingly utilized in fields such as medicine, agriculture, industry, and energy, human and environmental exposure to these materials has significantly grown. The unique properties of nanoparticles—including their small size, large surface area, and reactivity—enable them to interact with biological systems in ways that differ from conventional materials. This raises concerns about their potential toxicity, notably their ability to penetrate biological barriers, generate oxidative stress, alter cells and tissues, and even disrupt immune and endocrine functions. From an environmental perspective, nanoparticles can contaminate soils, water, and ecosystems, impacting flora and fauna. Current research aims to understand the mechanisms of nanoparticle toxicity, assess their bioavailability, persistence, and accumulation in the environment, and develop risk management strategies. The challenge lies in balancing the benefits of nanotechnologies with the need to protect health and the environment.