IT service is increasing becoming a critical resource firms have to utilize effectively and efficiently. As the importance of IT service increases, the knowledge sharing between IT service people and users becomes more and more important. In this study, the IT service quality is posited as a critical independent construct that influences knowledge sharing attitude of users which in turn change the knowledge sharing intention. Service satisfaction is placed as a mediator between the quality and attitude to compare direct and indirect effect in the model. Results show that (1) IT service quality influences the knowledge sharing attitude of users directly, and indirectly through service satisfaction, (2) at the same time, however, the direct path from quality to attitude is found to be stronger than the indirect path through satisfaction, and (3) interestingly, satisfaction seems to have no direct effect on intention, but only through the attitude change as can be inferred from the theory of reasoned action. Outcome of this study implies the importance of IT service quality in improving the knowledge sharing activities between users and developers, and interestingly the aim of quality would not be targeted on satisfaction but on attitudinal changes.