Why and when people share their knowledge has received enough academic attention, while little attention devoted to why and when people hide knowledge at workplace. Drawing on the social exchange theory, the norms of reciprocity, and the psychological ownership theory, this study examines how territoriality directly and under the indirect influence of knowledge hiding affect task performance and workplace deviance in organization. The study of 198 triads (ie., the team leader, the team leader's subordinate, and team leader's supervisor) reveals that territoriality and knowledge hiding have negative effect on task performance but positive influence on workplace deviance (ie., interpersonal and organizational deviance). Another contribution of the study is that knowledge hiding negatively mediates the influence of territoriality on task performance and workplace deviance. Implications for theory, practice and future research have been discussed.