<p>The possible growth and production of wheat have been negatively influenced by salinity stress, which is a&#xa0;critical environmental factor. Therefore, our study aimed to determine the salinity tolerance threshold of two wheat cultivars (Amin and Barzegar) via photochemical efficiency and ion homeostasis under eight salinity levels (0.5, 2, 4, 6, 8, 10, 12, and 14 dS m⁻¹) using a&#xa0;completely randomized design with three replicates. Both wheat cultivars experienced a&#xa0;decrease in the investigated leaf area from the 2 dS m⁻¹ salinity level, with the shoot and root dry weight trends remaining unchanged until the 6 dS m⁻¹ level, followed by a&#xa0;change in the shoot and root dry weight trends. Some significant interactions between salinity stress and cultivars were found in photosynthetic pigments and chlorophyll fluorescence parameters. Increasing salinity stress reduced the F_v/F_m, F_v/F₀ and YPII in both wheat cultivars. However, a&#xa0;significant increase in non-photochemical quenching (NPQ) was observed as salinity intensity increased. The increase in NPQ was approximately 30% lower in Barzegar than that in Amin under severe stress. The antioxidant enzyme activity, K⁺&#xa0;concentration, and K⁺/Na⁺ ratio in the cultivar Barzegar were remarkably higher than those in Amin; meanwhile, Amin maintained a&#xa0;higher Na⁺ concentration under salinity stress. Accordingly, photosynthesis parameters, redox, and ionic homeostasis were observed to be linked with salinity tolerance, and Amin and Barzegar were recognized as the sensitive (salt’s tolerance threshold: 3.67 dS m⁻¹) and tolerant (salt’s tolerance threshold: 7.13 dS m⁻¹) cultivars, respectively. Therefore, some wheat cultivars, such as Barzegar, could manage environmental stress by improving antioxidant enzyme activities, K⁺&#xa0;concentration, and the K⁺/Na⁺ ratio to maintain a&#xa0;higher tolerance threshold when salinity stress is raised.</p>