The olive tree is an emblematic fruit tree species of the Mediterranean basin facing drought. In this study, we estimated the effects of inoculating one-year-old olive trees of the 'Moroccan Picholine' and 'Arbequina' cultivars with arbuscular mycorrhizal fungi (M) and plant growth-promoting-bacteria (B), both individually and in combination (M + B), focusing on morpho-physiological, anatomical and nutritional changes. We evaluated these effects under two levels of water stress: well-watered conditions (WW) at 75% field capacity (FC) and drought stress (DS) at 25% FC. However, biofertilizers mitigated these effects by improving growth parameters. The M + B application increased growth parameters by 35%, 48%, 24%, and 36% in 'Moroccan Picholine', and by19%, 24%, 38%, and 64% in 'Arbequina' for the number of leaves, number of buds, growth rate, and leaf area, respectively, compared to the stressed controls. In summary, the results show that the 'Moroccan Picholine' cultivar has greater resistance to drought than 'Arbequina', making it a promising choice for arid conditions. These findings highlight the potential of biofertilizers as a sustainable approach to enhancing olive tree resilience in arid regions, contributing to agricultural sustainability.