The literature currently in circulation does not provide a clear picture of how melatonin affects okra plants under water regime stress. Thus, the objective of this study is to look into the impact of one of these biochemical substances on okra plants growing in stressful water regime environments. The obtained results showed that water regime stress (60, 80 and 100 % from ETo), foliar application of melatonin (100, 150 and 200 mg/L) significantly enhanced the height of plants, index of leaf area, number of branches per plant, root length, root weight, chlorophyll content, early yield, No. of fresh pods/plant, fresh pods weight/plant, fruit shape index, average pod length, average pod diameter, dry pod weight per plant, total fruits yield, TSS, Vitamin C and relative water content as comparison with the untreated plants. In contrast, the activity of the catalase enzyme was significantly lower than in the untreated plants. In conclusion, it can be said that applying melatonin topically is a good way to improve the productivity and growth performance of okra cultivated in water regime stress situations and the best treatment at all parameters was 100 % from ETo + 200 mg/L melatonin, but there were no significant differences between this treatment and 80 % from ETo + 200 mg/L melatonin.