Various studies have been conducted to study the relationship between job involvement and organizational citizenship behavior but a very little work have been done to study the impact of both job involvement and organizational commitment on “organizational citizenship behavior”. Thus the purpose of the study is to find out the relationship between job involvement, organizational commitment and organizational citizenship behavior and also to study if there is any impact of job involvement and organizational commitment on Organizational citizenship behavior among service and manufacturing sector employees. The study has been done on 150 employees of both service and manufacturing sector with the help of questionnaire, where job involvement and organizational commitment were taken as independent variables and Organizational citizenship behavior as dependent variable. Multiple regression was applied with the help of SPSS. The result indicated that there is a significant impact of independent variables on dependent variables, that is, there is a significant impact of Job involvement and Organizational commitment on OCB.