Reactive oxygen species (ROS) is a metabolic side product of oxidative stress process, which causes several diseases like atherosclerosis, cancer, etc. In defense of ROS, antioxidants play a key role in combating them. As the process of aging increases, the level of antioxidants in our body decreases and thereby needs utmost attention for its repair process, which is generally administered externally. Plant products serve a best source for controlling these activities by its own metabolic pathway. Studies on the antioxidant activities of Maytenus emarginata leaf extracts are lacking. Antioxidant activity of the methanol extract of Maytenus emarginata was determined by DPPH free radical nitric oxide scavenging assays, superoxide ion scavenging assays, ABTS, and iron chelating methods. Preliminary phytochemical screening revealed that the extract of Maytenus emarginata leaves possesses phenols, flavonoids, steroids, glycosides, saponins, tannins, and triterpenoids. The extract showed significant activities in all antioxidant assays compared to the standard antioxidant (ascorbic acid) in a dose-dependent manner, and remarkable activities to scavenge ROS may be attributed by the presence of the above active compounds in the leaves. The amount of total phenolics and flavonoid contents were also estimated. The DPPH, ABTS, Nitric oxide, superoxide, and iron chelating IC(50) values of the methanolic extracts were 12.44, 24.27, 22.41, 5.85, and 2.74 μg/mL, respectively. The total phenolic content of the methanolic extract was 10.69 mg CA/g, whereas the total flavonoid was 1.56 mg CAE/g. The antioxidant activities were correlated with the total phenolic content. This result suggests that the relatively high antioxidant activity of the methanolic extract compared to standard could be possibly be due to its high phenolic content.