The main goal of this study was to determine the antioxidant activity of twelve medicinal plants (Averrhoa carambola (Oxalidaceae), Buchanania lanzan (Anacardiaceae), Calophyllum inophyllum (Clusiaceae), Celastras peniculatus (Celastraceae), Clerodendron multiflorum (Verbenaceae), Luffa acutangula (Cucurbitaceae), Morinda citrifolia (Rubiaceae), Ocimum gratissimum (Lamiaceae), Paltophorum ferrugineum (Papillionaceae), Phyllanthus fraternus (Euphorbiaceae), Triumfetta rotundifolia (Tilliaceae), Ziziphus nummularia (Rhamnaceae) belonging to different families. Antioxidant activity was determined by using different methods like DPPH (2,2-Diphynyl, 1-picrylhydrazyl) free radical scavenging assay, hydroxyl radical scavenging assay, superoxide anion radical scavenging assay and reducing capacity assessment. The plants were extracted individually by cold percolation method using different organic solvents (petroleum ether, acetone and methanol) depending on their polarity. Ascorbic acid was used as standard to determine DPPH free radical scavenging activity and reducing capacity assessment. Gallic acid was used as standard to determine hydroxyl radical scavenging activity and superoxide anion radical scavenging activity. Amongst the twelve plants studied, acetone and methanolic extract of Paltophorum ferrugineum showed the best radical scavenging activity and reducing capacity assessment.