The antioxidant capacity of extracts of different parts of Cucurbitaceae vegetables was evaluated by DPPH (2, 2-diphenyl-1-picrylhydrazyl) and ABTS (2, 2'-azino bis (ethyl benzothiazoline 6)-sulphonic acid) methods. Total phenolic content (TPC) and total flavonoid content (TFC) were also determined. The correlation of TPC, TFC, DPPH, and ABTS in different extracts of Cucurbitaceae vegetables was analyzed. The peel extracts of studied vegetables had the highest TPC, (C. grandis 3.00±0.86, T. cucumerina 3.24±0.70 and C. moschata 3.12±0.06 mg gallic acid equivalent (GAE) g-1 DW) and TFC (C. grandis 18.96±1.5, T. cucumerina 13.92±1.41 and C. moschata 15.31±0.97 mg rutin equivalent (RE) g-1 DW). The maximum antioxidant potential was obtained by the ABTS method in peel extracts of C. grandis (78.7%) and C. moschata (63.5%) while in pulp extract of T. cucumerina (50.1%) at 10 μg/mL. The percent radical scavenging activity (% RSA) by the DPPH method found maximum for peel and pulp of C. grandis (45.15 and 45.15%, respectively) and peel of T. cucumerina (45.15%) and C. moschata (34.15%). The EC50 obtained in the ABTS method was 0.54 and 7.15 μg/mL for C. grandis and C. moschata, respectively while 0.81 μg/mL for the pulp of T. cucumerina compared to standard ascorbic acid (1.05 μg/mL). The EC50 calculated in the DPPH method was 11.78 μg/mL, 13.34 μg/mL, and 21.00 μg/mL for C. grandis, T. cucumerina, and C. moschata peel respectively compared to the standard Butylated hydroxytoluene (BHT). Among each variable, the correlation between ABTS and TPC provided the highest positive correlation (r = 0.998, p< 0.05) in peel extracts.