Selenium is an essential micro mineral required for maintaining animal health and production. Role of Se in intra- and extra-cellular antioxidant systems is extensively studied. Dietary supplementation is advocated by many researchers to boost immunity which necessitates its synthesis in laboratory. The supplementation of Se can be done either as inorganic, organic or lately in nano form. The synthesis of nano-Se can be done either by following physical, chemical and biological methods. Se in its nano form has more surface area and thus reported to produce better responses in animals and birds. The Se concentration in organs were higher in nano- Se supplemented broiler birds as compared to its inorganic sources. The Se concentration was high in eggs laid by Se supplemented birds from different sources whereas the deposition efficiency was higher for nano Se than sodium selenite. Nano-Se improved growth performances like feed conversion ratio, body weight gain, even in heat stressed birds. Nano-Se supplementation improved humeral immunity manifested by the elevated serum immunoglobulin levels. Nano-Se improved immune response through elevated muscle and liver glutathione peroxidase (GSHPx) activity, decreased malonaldehyde activity, increased catalase enzyme activity and significant decrease in thiobarbituric acid reactive substance (TBARS) value. Improved anti-oxidative status was instrumental in improving meat quality that resulted in decreased muscle drip loss and improved storage quality of meat in heat stressed birds. Se supplementation to layers improved albumen quality, shell strength and thickness and haugh unit.