Abstarct: In Iran, most pistachio cultivation areas are located in the margins of the desert, and one of the main challenges in these regions is soil and irrigation water salinity, which negatively affects plant growth and performance. Mycorrhizae, as symbiotic fungi, play a significant role in enhancing plant growth, while melatonin has recently gained attention as a growth phytohormone under stress conditions. To this purpose, an experiment was conducted in the form of a completely randomized factorial design in the greenhouse of the Faculty of Agriculture at Shahroud University of Technology during the agricultural year 2023-2024 with four replications. The factors under investigation included salinity caused by sodium chloride at three levels (zero, 75, 150 millimolar), the melatonin at two levels (zero and 100 µM), and the mycorrhizae at two levels (with mycorrhizae and without mycorrhizae). The results indicated that with increasing salinity stress, growth parameters such as fresh weight and dry matter percentage of aerial parts significantly decreased. Melatonin at a concentration of 100 micromolar positively influenced root growth and increased its dry weight. Additionally, mycorrhizal treatment increased root length, although it reduced root weight. At a salinity level of 150 millimolar, the synergistic effect of applying melatonin and mycorrhizae in reducing the effects of salinity on the fresh weight of pistachio seedlings was evident, with the combined application of these two factors showing better results than their individual applications. Furthermore, mycorrhizae had a significant effect on increasing the effective quantum efficiency of photosystem II, with the average quantum efficiency rising from 0.76 in the absence of mycorrhizae to 0.8 in their presence. Mycorrhizae also reduced proline levels, while melatonin significantly increased proline and malondialdehyde enzyme levels in the absence of mycorrhizae. Melatonin increased sodium absorption in leaves, while mycorrhizal treatment had the greatest effect in reducing sodium levels in pistachio seedling leaves. Melatonin alone reduced potassium levels in roots, while mycorrhizae increased potassium absorption under non-saline conditions; however, potassium absorption decreased with increasing salinity. The highest potassium absorption in roots occurred when both mycorrhizae and melatonin were used together. Overall, the simultaneous application of mycorrhizae and melatonin is proposed as an effective strategy for mitigating salinity-induced damage and improving the performance of pistachio plants.