In order to assess the response of four popularly grown black gram (Vigna mungo L.) genotypes (T9, PU 19, USJD 113, KU 301) under osmotic stress, the present study was carried out by monitoring the changes in relative leaf water content (RLWC), carotenoid, total soluble protein (TSP), membrane lipid peroxidation (MDA), H2O2 scavenging capacity, and the activities of superoxide dismutase (SOD) and catalase (CAT). Osmotic stress was applied by withholding irrigation for 15 consecutive days at vegetative, flowering and pod filling stages. Under stress condition, several fold increase in the content of MDA, H2O2 scavenging activity and antioxidant enzyme activity was recorded while, RLWC, carotenoid and TSP were found to decrease. Flowering stage was found to be most sensitive in terms of economic yield. The genotype T9 experienced lowest reduction in yield (12.10–33.91%) with maximum value of drought tolerance index (DTI) (7.48) which can be attributed to its higher tolerance capacity to drought. On the other hand, USJD 113 had the highest yield loss (26.48–60.99%) and lowest DTI (6.07) value, indicating its susceptibility towards osmotic stress.