Global climate change and increasing water scarcity pose significant threats to melon production, particularly in semi-arid regions where drought stress severely limits plant growth and yield. To address these challenges through sustainable microbial interventions, this two-year field study evaluated the effects of different Plant Growth-Promoting Rhizobacteria (PGPR), including Bacillus subtilis, Bacillus megaterium, Enterococcus spp., and their consortium, on plant growth, yield, and leaf nutrient composition of melon (Cucumis melo L. cv. K & imath;rka & gbreve;a & ccedil; 637) under irrigated and non-irrigated conditions. PGPR applications generally improved vegetative growth parameters, such as stem diameter, main stem length, and leaf number, compared with the control, with Bacillus subtilis consistently showing the most pronounced effects across both growing seasons. Under non-irrigated conditions, Enterococcus spp. application resulted in a marked increase in plant fresh weight compared with the control. Although total fruit yield was not significantly affected by PGPR treatments, leaf nutrient analysis revealed that Bacillus subtilis significantly enhanced magnesium (Mg) and iron (Fe) contents under both irrigation regimes. These findings indicate that PGPR, particularly Bacillus subtilis, can improve vegetative growth and nutrient uptake of melon plants and contribute to alleviating the adverse effects of drought stress, highlighting their potential role in sustainable melon production under water-limited conditions.