Antioxidants, cysteamine, and melatonin have an important role in mitochondrial membrane potential (ΔΨM), in vitro nuclear maturation, and the developmental competence of oocytes. A comprehensive study was planned to investigate the effect of cysteamine 50 µM and melatonin 10-9 mol L-1 as antioxidants on ΔΨM, in vitro nuclear maturation, and developmental competence of ovum pick-up (OPU) derived Sahiwal oocytes. Culturable grade OPU-derived Sahiwal oocytes were divided into three in vitro maturation groups cultured in TCM-199 supplemented with cysteamine 50 µM, melatonin 10-9 mol L-1, and TCM-199 alone, for assessing nuclear maturation by Lamin/ DAPI and developmental competence of oocytes. ΔΨM was assessed by JC-1 staining in the pre-maturation group and post-maturation cysteamine, melatonin, and control groups. Red to green ratio of fluorescence intensity on JC-1 staining was higher (p < 0.05) in melatonin (1.19±0.04) and cysteamine (1.09±0.04) supplementation groups as compared to control (0.81±0.10) and pre-maturation (0.71±0.03) groups. ΔΨM improved post-maturation in all the treatment and control groups compared to the pre-maturation group (0.71±0.03). Melatonin supplementation improved (p < 0.05) M-II stage oocytes (6.5±0.65, 68.13 percent) as compared to cysteamine supplemented (5.25±0.25, 55.63 percent) and control (4.75±0.25, 50.63 percent) groups. The COC expansion rate was higher in the antioxidant-supplemented group. Fertilization rate, cleavage rate, and blastocyst rate were higher (p < 0.05) in the melatonin-supplemented group (92.31, 59.17, and 20.56 percent) as compared to cysteamine supplemented (82.96, 41.48 and 11.39 percent) and control (75.28, 27.59 and 5.19 percent) groups, respectively. In conclusion, cysteamine and melatonin supplementation as antioxidants in the in vitro maturation media improved (p < 0.05) ΔΨM. Significant improvement in MII stage oocytes, cleavage, and blastocyst rate in OPU-derived Sahiwal cattle oocytes by supplementation of melatonin to the IVM medium compared to cysteamine supplemented and control groups. Melatonin improved both cytoplasmic and nuclear maturation thereby improving the developmental competence of OPU-derived Sahiwal oocytes. Cysteamine supplementation improved the cytoplasmic maturation and not the nuclear maturation and developmental competence of OPU derived Sahiwal oocytes.