The aim of the present study was to evaluate Sargassumwightii Greville ex J. Agardh for its antioxidant activity. Two different solvent extracts namely methanol and ethyl acetate were used for the study. Three different assays such as DPPH, Hydroxyl Radical Scavenging activity and Total antioxidant activity assays were used for the study. The results of the study showed a significant activity in all the studied assays. The ethyl acetate extract showed higher antioxidant activity than methanol extract. As the concentration increases there was a remarkable increase in radical scavenging activity.