In the rapidly changing business environment, knowledge has been recognized as a core asset for sustaining an organization's competitive advantage. In addition, knowledge sharing is one of the key elements of knowledge management, emphasizing external knowledge sharing beyond initial internal knowledge sharing. However, while knowledge management research emphasizes knowledge sharing, which is a positive aspect, research on preventing knowledge leakage that can have negative consequences is relatively lacking. Companies have tried to minimize the negative effects of knowledge management but many knowledge leakage accidents are still occurring. Therefore, this study aims to examine the effects of external factors based on deterrence theory and internal factors based on self-determination theory on knowledge leakage intention focusing on tacit knowledge. The results of the empirical analysis of 100 data sets collected through a scenario-based survey show that certainty of sanctions, social disapproval, and competence are found to have a significant effect on reducing tacit knowledge leakage intention. Furthermore, informal sanctions have a greater impact on tacit knowledge leakage intention than formal sanctions and external factors have a greater effect on tacit knowledge leakage intention than internal factors.