This study focuses on to explore the impact of social power on Organizational Citizenship Behaviour (OCB) and the role of OCB as a mediator of the relationship between social power and personal and organizational effectiveness. Data were collected by administering self rated questionnaires to male middle level executives (N = 250) in face to face condition from motor cycle manufacturing organisations based in northern India. The mediator analysis (by using AMOS) showed that all the fit indexes were in the acceptable range which indicates that OCBs has mediated significantly between social power and effectiveness. Other results as analyzed through multiple regression analysis showed the significant impact of social power on the dimensions of OCB and effectiveness as it was hypothesized. The study suggests the potential benefits of using positive forms of social power by supervisors as part of their managerial style in order to enhance OCBs and in turn increasing personal and organizational effectiveness. This study advances the research on the concept of OCB and social power in Indian work context.