Enhancing stress tolerance and productivity in mung beans under moisture-scarce, rainfed arid regions remains a pressing challenge. Acetic acid (AA) has recently emerged as a cost-effective agronomic intervention with the potential to enhance crop growth and resilience under moisture-deficit conditions. The present study investigated the effects of different doses of acetic acid (AA) concentrations (25 and 50 mM for foliar spray) and application methods, i.e., seed soaking (SS) at 5 mM and 10 mM, foliar spray (FS) at 25 and 50 mM, and their combination on the growth, physiological traits, and yield of mung bean (Vigna radiata) under rainfed conditions, using a factorial randomized block design with three replications. Results revealed that AA at 25 mM, when applied as a foliar spray or combined with seed soaking, significantly improved plant height, leaf area index, dry matter accumulation, nodulation, chlorophyll content, and antioxidant enzyme activities (p < 0.05). The most pronounced effect was observed with the combined application of AA through seed soaking (10 mM) + foliar spray (25 mM), which resulted in higher relative water content and membrane stability, nitrate reductase activity, and reduced oxidative stress index. The reproductive attributes, including flowering duration, number of flowers, and pod fertilization efficiency, were significantly improved under low-dose AA (25 mM) application. The yield increased to 10.32 q ha(-1) under AA 25 mM (SS + foliar). This corresponded to a 15.4% improvement over the control. The response at 25 mM AA was statistically comparable to that at 50 mM AA. This suggests that the higher dose did not provide extra benefits, making the lower concentration more efficient. The findings indicate that acetic acid has significant potential as a sustainable and cost-effective biostimulant for enhancing drought resilience and augmenting mungbean productivity in hot arid conditions.