Derived from leaves of evergreen herb Camellia sinensis, green tea is known for its significant human health benefits. Once primarily consumed in Asia and North Africa, green tea is becoming increasingly available around the world with an increase in its average annual growth. There has been a tremendous change in the consumption pattern of green tea, a prime drive of which is the increasing knowledge about and marketing of its health benefits. The most notable health benefit of green tea is its powerful antioxidant potential, which helps prevent cellular damage from certain oxidation reactions in the body at the molecular level. Green tea is attributed to health claims which include the prevention of skin cancer, lower blood pressure, the prevention of cardiovascular diseases, neurodegenerative and kidney disorders, diabetes, respiratory distress, the inhibition of clinical and opportunistic microbial infections, and many more. The rich presence of polyphenols in green tea is likely responsible for its multiple health benefits. in vitro and in vivo epidemiological evidence suggests the importance of green tea polyphenols in exerting antioxidant activities which confer medicinal and food value. Major polyphenols found in green tea include the catechins, such as epigallocatechin gallate, epigallocatechin, epicatechin 3- gallate, epicatechin, and catechin gallate. These catechins have shown promise in the promotion of cardiovascular health, the prevention of cancer, skin protection, the reduction of high cholesterol levels, diabetes, impaired immune function, diarrhoea, fatigue and infection. There is a highly significant relationship between phenolics, flavonoids and the antioxidant activity of green tea, while the amount of phenolic, flavonoids and antioxidants are the parameters depicting the quality of tea according to their biological properties. This book is an informative forum highlighting research on the antioxidant activity of green tea pertaining to its health benefits. The book is organised into seven chapters that provide a comprehensive review of the antioxidant activity of green tea and its associated health benefits. The book outlines useful information and improves the fundamental knowledge regarding the processing of green tea, its chemical components, their role as antioxidants and usefulness as nutraceuticals.