The purpose of study is to explore the relationship between Job Satisfaction and Organizational Citizenship Behavior (OCB) among employees working in banking sector of Pakistan. 350 managerial level employees from banking sector have contributed in this study by filling the questionnaire. The survey was conducted to test the hypothesized relationship between job satisfaction and organizational citizenship behavior of the banking employees. The 5-point Likert-scale research instrument for job satisfaction and its aspects was developed, based on the work of Herzberg two factor theory. Dimensions of OCB were developed based on the work of Parsons and Shrills (1951). Thus, in this research, OCB is defined as being composed of 4 main dimensions, namely, 1) Interpersonal Helping; 2) Individual Initiative; 3) Personal Industry; and 4) Loyal Boosterism. The results reveal significant information that can help organizations to increase job satisfaction by improving the organizational citizenship behavior.