Recently, several researchers have questioned the predicting power of intention to actual system usage (Burton-Jones & Straub, 2006; Jasperson, Carter, & Zmud, 2005; Kim & Malhotra, 2005; Kim, Malhotra, & Narasimhan, 2005; Limayem & Hirt, 2003). In this article, we report a study that investigates the gap between intention and usage by observing an Internet-based knowledge management system, SCTNet, from the perspective of volitional control. Relying on the theory of planned behavior and the theory of action control, we investigate four types of volitional control mechanisms that may impact people's knowledge-sharing practices. Our results show that in knowledge-management-based knowledge sharing, people do not always perform in a manner consistent with their espoused beliefs. This intention–action inconsistency can be explained by perceived self-efficacy, but not by intention and controllability. In addition, a person's action/state orientation moderates his or her enactment of intention toward knowledge sharing into behaviors. The main theoretical implication of this study is that the study of knowledge-management-based knowledge sharing has to go beyond intention to include the investigation of both the actual behaviors of knowledge sharing and the volitional control constructs that predict these behaviors. Furthermore, previous research has shown that the environment interacts reciprocally with individuals' psychological control mechanisms in regulating their behaviors. Thus, the management must focus on the social and cultural attributes of organizational settings that may strengthen people's volitional control in practicing knowledge sharing.