The constant evolution and applications of metallic nanoparticles (NPs) have increased the potential for living organisms to be exposed to them. Among the most widely used are zinc oxide nanoparticles (ZnO-NPs). Understanding the atomic impacts of ZnO-NPs in natural frameworks is significant. This review examines the primary mechanisms that induce cell toxicity through exposure to ZnO-NPs, with a particular focus on mitochondrial damage, based on in vitro research models. Cytotoxicity of ZnO-NPs Scientific evidence indicates that in vitro ZnO-NPs have a cytotoxic effect that depends on factors such as size, shape, synthesis method, and the function of the exposed cells. ZnO-NPs interact with the extracellular region, leading to increased intracellular Zn2+ levels. Mitochondrial Damage: The mechanism by which intracellular ZnO-NPs interact with organelles like mitochondria remains unclear. Mitochondria are crucial organelles that participate in numerous cellular processes, including survival, death, and metabolism. ZnO-NPs have been shown to: Cause Increment in intracellular reactive oxygen species (ROS), especially superoxide levels. Decrease mitochondrial membrane potential (MMP), affecting membrane permeability and leading to cell death. Induce cell death through caspase activation and the intrinsic apoptotic pathway. The expression of pro-apoptotic qualities after ZnO-NP introduction can be impacted by components such as NP estimate, morphology, cell sort, formative arrange, vitality request, introduction time, and measurements. Mitochondrial Homeostasis: To prevent the release of pro-apoptotic proteins, damaged mitochondria undergo mitophagy for elimination. Mitochondrial biogenesis processes then replace the lost mitochondria to maintain adequate ATP levels and cellular homeostasis. In summary, this review highlights the complex mechanisms by which ZnO-NPs can induce toxicity, with a particular emphasis on their detrimental effects on mitochondrial function and the subsequent cellular responses to maintain homeostasis.