The present study entitled "Efficacy of Behaviour Modification and Yoga among the Adolescent" My study is the outcome of the gracious guidance and help extended by a number of individuals. The foremost among them, is my research guide, Dr. MVR Raju, Professor and Head of the Department of psychology and parapsychology, Andhra University, Visakhapatnam who has motivated me to work on a socially and educationally relevant topic for research study. He has been kind enough to constantly supervise my work at all stages of its progress, till its completion. But for his continuous support, this thesis would have not been possible and a reality. I convey my deep sense of gratitude to him in this regard. I also extend my sincere thanks to Dean and Faculty of Psychology and Parapsychology for their unstinted support and encouragement. I feel immense pleasure in thanking all the respondents for their cooperation in giving information and sharing their experiences. Finally, I express my gratitude to the scholars and particularly to Dr. K. Taraka Rama Rao who have helped in collecting the data required for my thesis. Last but not the least, I acknowledge my heartfelt thanks to my wife, Dr. Anantha Lakshmi, M.S. D.G.O who had been my constant source of inspiration in completing this thesis.