<p>Selenium (Se) is a trace element that is beneficial for the growth and development of plants. It plays a crucial role in various physiological processes, including plant growth, ion hemostasis, and defense mechanisms. Se in plants was recognized to enhance heavy metals (HMs) tolerance, with potential implications for agricultural productivity and sustainability. Selenium nanoparticle (Se-NPs) supplementations have emerged as a promising alternative and practical tool to enhance the tolerance of plants against cadmium (Cd) toxicity. Their small size, reactivity, and surface area make them suitable for use in environmental remediation, particularly in the removal of Cd and other HMs. In agricultural practice, they offer many benefits, such as improvement of growth and mineral nutrition, enhancement of antioxidant defense, stomatal function, and photosynthesis, and reduction of Cd uptake. Cd is a toxic element that can have detrimental effects on the growth and development of plants. When plants are exposed to high levels of Cd, they can experience a range of negative impacts on their physiological processes. One of the most significant effects of Cd on plants is the inhibition of root growth, which can ultimately lead to reduced nutrient uptake and overall stunted growth. Additionally, Cd can interfere with photosynthesis, affecting the plant's ability to produce energy and metabolize nutrients effectively. This paper provides an overview of Se and Se-NPs to mitigate Cd toxicity in plants, as well as its role to enhance mineral nutrition, photosynthetic activity, and oxidative defense system under Cd stress.</p>