Salinity as major problem adverse effects plants productivity .One of the targets of researchers in agriculture is to mitigate the effects of salinity using new methods. The applicated of nano technologies and bio-fertilizers are among the new methods to mitigated the effects of salinity stress .Since the effects of nano materials and fish waste bio- fertilizer on stevia plant (Stevia rebaudiana Bertoni) under salinity stress is unclear, an experiment was conducted to investigate the effects by applying different concentrations glycine betaine (foliar application) at three levels (0, 15, 30 mg/l) and simultaneous application of fish waste bio-fertilizer (foliar application) at one level (15% (v/v)) on stevia plants grown under salt stress conditions (0, 30, 60, 90 mM of NaCl). The results showed that salinity caused a 48/02% decrease in growth traits, 51/38% of photosynthetic pigments, and an increase 71/24% antioxidant enzymes, 67/44% malondialdehyde (MDA) and 88/22 % of electrolyte leakage (EL). On the other hand, simultaneous application of glycine betaine and fish waste bio-fertilizer mitigated the effects of salinity stress by enhancing growth parameters especially at the highest salinity level (90 mM). Overall, application of glycine betaine especially when used at a concentration of 30 (mg/l) and liquid fish waste bio-fertilizer could be considered as a sustainable, for the mitigating of salinity stress effects in stevia plants and potentially other crops.