It has been shown that application of inorganic nano-materials on cereal plants during their growth cycle improves the rate of plant productivity by supplying a micro-nutrient source. This study aimed to evaluate the impact of seed priming with zinc oxide nanoparticles (ZnONPs) (0.0 and 100 ppm) on maize Triple-hybrid 321 seedling grown in soil containing different levels of salinity (0.0, 50, 100 and 150 mM NaCl) for three weeks. Parameters were determined for growth (fresh and dry mass (FM, DM), osmotic concentration (OC) of organic/inorganic solute, photosynthesis pigment content (PPC), and selective antioxidant system (AOS) enzymes that might be involved in the stress remediation. The toxic effects of salinity on Zea mays L plants were assessed by determining growth parameters, antioxidant enzymes activity [catalase (CAT), peroxidase (POX) and ascrobate peroxidase (APOX)], osmotic concentration (OC) of organic/inorganic solute organic solutes (soluble sugars, soluble proteins, free amino acids and proline) and ions content (Na+, K+, Ca2 and Mg2+) in the presence or absence of ZnONPs. The obtained results revealed that, salinity stress resulted in a significant increase in antioxidant enzymes activity, organic solutes and ions content which are associated with significant reduction in growth parameters compared with control plants. Seed priming with ZnONPs significantly alleviated the harmful effect of salinity on Zea mays L seedlings and increased the activity of antioxidant enzymes, organic solutes and ions content (Na+, K+, Ca2+ and Mg2+), which could be an induced defensive mechanism against salinity stress.