Plants are confronted with unexpected and diverse environmental pressures in the era of climate change. Plant development and metabolism are significantly hindered by both abiotic and biotic stress, which leads to reduction of crop yield by 50-88% worldwide. Nevertheless, plants have developed a broad aspect of defence mechanisms across multiple levels in response to environmental challenges. The plant defence mechanisms involve molecular-level modifications to morphological, physiological, anatomical, and biochemical characteristics. In addition, nanotechnology is a promising area of innovation in the field of plant sciences, generating novel concepts for comprehending the optimal survival mechanism of stressed plants. Nanomaterials are considered regulatory molecules for plants due to their ability to modulate an extensive array of physiological and biochemical processes, plant immune system, including stress-related gene expression, hormonal regulation, and activation of the anti-oxidative defence system. However, understanding the intricacies of interactions between nanomaterials and plants in terms of antioxidative and immunomodulatory effects are not yet fully explored. Thus, the present review elucidates the potential antioxidative and immunomodulatory regulation of nanomaterials in plants via enhanced antioxidative system, reduced oxidative stress level, and reactive oxygen species (ROS) generation, upregulation in defence related gene expression, phytohormone regulation, and miRNA regulation. Further, toxicity behaviour of nanomaterials over plants, and prospects have also been discussed to provide future directions in the area. Overall, this review will provide a new insight for development of nanomaterials with potential immunomodulatory effects in plants in terms of resistance to biotic and abiotic stress.