Natural antioxidants and their association with health benefits have gained unprecedented attention in recent years. They have multiple functions in biological systems and mainly defense against oxidation that produce free radicals in food, chemicals and in living systems. During the past decades, synthesized nanoparticles from marine organisms and many of these substances have been demonstrated to posses exciting biological activities. With this background, S. wightii and its AgNPs were analyzed for their antioxidant properties. Green synthesis of silver nanoparticles was carried out using the aqueous extract of S. wightii. The aqueous extract of S. wightii showed significant potential for the quick reduction of silver ions. The antioxidant properties of green synthesized AgNPs was carried out and it showed significant activity when compared with standard. The present work of green synthesis of silver nanoparticles using S. wightii appears to be cost effective, eco-friendly, and an alternative to conventional method of synthesis. In the present study, the aqueous extract and its synthesized AgNPs showed high antioxidant activity to the best of our knowledge. Hence, green synthesized AgNPs of S. wightii can be used as a potential therapeutic drug for various diseases due to its bioactive properties.