Searching sustainable management techniques to enhance plant resistance to drought is crucial for agriculture in stressful scenarios. This study aimed to investigate the role of Plant Growth-Promoting Bacterial (PGPB) strains on forage cactus pear performance under drought. Trials were conducted in greenhouse using forage cactus plants in randomized block experimental design, 8 × 2 factorial scheme, consisting of eight inoculation treatments [inoculation with Paenibacillus sp. IPACC38 and IPACC55, and Bacillus subtilis IPACC29 strains combined with and without nitrogen (N) fertilization] and two water regimes [control at 50% field capacity (FC) and drought at 25% FC]. Drought significantly decreased plant growth across all treatments, regardless of N/inoculation treatment. The best performance under drought was observed in plants grown without N and inoculated with IPACC29 and IPACC38 strains. Improved performance under drought was closely related to PGPB’s capacity to provide N accumulation for strategic photosynthetic pigments content, resulting in better root growth and plant development. Our findings reveal that IPACC29 and IPACC38 are the most promising PGPB strains for inoculating forage cactus pear, activating important defense responses against drought. This system offers alternative for cultivating cactus under water restriction and reduced N availability to increase green forage biomass production in dry regions.