Abstract Background Salinity stress is one of the most serious abiotic stress affecting adversely plant growth, various metabolic processes, and crop production. Using different osmoprotectants such as trehalose in alleviating salinity stress adverse effects is very important for plant production. So, the present study investigated the physiological role of trehalose (Tre) in improving wheat tolerance to oxidative stress induced by salt stress. Results Salinity stress (6.25 dS/m) caused marked significant decreases in wheat plant growth parameters (shoot height, fresh, and dry weights of the shoot) accompanied by significant increases in lipid peroxidation, hydrogen peroxide contents, and lipoxygenase enzyme (LOX) activity. Osmoprotectant compounds such as glucose, sucrose, trehalose, total soluble sugars (TSS), free amino acids, and proline increased in wheat plants irrigated with saline water compared with unstressed control plant. On the other hand, Tre foliar treatments (10 mM and 50 mM) proved to be effective in enhancing growth parameters and more accumulation of the tested organic solutes of leaves (glucose, sucrose, trehalose, and TSS) of salinity-stressed plants. Meanwhile, trehalose treatments with different levels caused significant decreases in lipid peroxidation, hydrogen peroxide contents, and LOX activity in normally irrigated and salinity-stressed plants. These decreases correlated with significant increases in total phenolic contents as compared with untreated control. Conclusion It could be concluded that foliar spray of trehalose was effective in improving wheat performance by reducing hydrogen peroxide free radical and by enhancing antioxidant compounds (phenolics), compatible osmolytes, and membrane stability.