The state of psychological equilibrium in school teachers is of great concern. As a truth, equilibrium is the most delicate, unstable state and gets disturbed even by a slight disturbance in its components. The causal factors of imbalance or disequilibria, in the psychological configuration of school teachers are plenty in number; the environment in which they are living and interacting with others, the work environment and the constitution of the person himself. The complexities of human life, changed structure of families, tough competition in all walks of life, rapid changes in the environment (such as Industrialization, Urbanization and Modernization), changing the values of society, social demand and expectations, work conditions, etc. have flooded the human minds of school teachers with tension and anxiety as they fail to cope with all of them simultaneously and effectively and this causes injury to their psychological well-being or mental health. The aim of the present study is to find out the effects of Yoga on Subjective Well-Being of school teachers. In this study, 36 school teachers are trained in Yoga for 48 days and their Subjective Well-Being is measured before and after Yoga. It is found that, there is a significant increase in the Subjective Well-Being due to Yoga training, thereby giving them a good mental and physical health.