This study evaluated the role of gibberellic acid [GA 3; (0, 100, 200, and 300 ppm)] in modulation of the growth, physiology, yield, and quality traits in two varieties (BARI Mung-6 and BARI Mung-8) of mungbean ( Vigna radiata L.). Irrespective of the two varieties (BARI Mung-6 and BARI Mung-8), 100, 200, and 300 ppm of GA 3 differentially modulated the tested parameters (relative water content, RWC; photosynthetic pigments: chlorophyll a, chlorophyll b, and carotenoids; growth parameters: fresh and dry weights of leaves, petioles, stems, and roots; yield contributing traits such as plant height, number of pods plant −1, number of grains pod −1, pod length, and 100-grain weight; quality traits such as grain nitrogen and protein). However, compared to the lowest GA 3 (100 ppm) and the highest GA 3 (300 ppm), the moderate concentration of GA 3 (200 ppm) led to highest values of leaf-RWC, where this parameter exhibited 16.1 and 13.4% increase in BARI Mung-8 and BARI Mung-6, respectively. Similarly, the tested herein growth parameters and the yield traits significantly increased up to the foliar application of the moderate GA 3 concentration (200 ppm), and thereafter these traits decreased with 300 ppm GA 3. The 200 ppm-led changes in the growth and yield traits were significantly higher in BARI Mung-8 when compared to BARI Mung-6. Considering the quality traits, GA 3 positively influenced the nitrogen and protein content in grains, where 200 ppm of GA 3 led to increases of 25.2% in N, and 17.7% in protein over control in BARI Mung-6; whereas, BARI Mung-8 exhibited 28.3% in N, and 18.3% in protein with 200 ppm GA 3 over control. Overall, BARI Mung-8 significantly responded to the foliar supply of 200 ppm GA 3 when compared to BARI Mung-6. Hence, in order to high yield and grain protein content, the application of 200 ppm GA 3 may be applied in V. radiata before and during flowering. The major mechanisms underlying the responses of the water relation, growth, and yield traits to the GA 3 concentrations need to be explored.