Affective commitment and intrinsic motivation to share knowledge are important issues in developing successful technology-mediated learning (TML) and knowledge management (KM) systems. This paper investigates an individual's social/self identities and affective commitment as important identity factors for perceived enjoyment to share knowledge by email and knowledge sharing attitude in the TML environment. An empirical test of the proposed model was conducted in the pilot test (n = 155) as well as the main test (n = 411). Identity factors (social/self identities and affective commitment) influence perceived enjoyment (R[superscript 2] = 0.52), and perceived enjoyment influences knowledge sharing attitude (R[superscript 2] = 0.51) in TML. The results of this study will help us understand the antecedents of effective knowledge sharing intervention in the TML environment, based on the integrated model of social identity theory, social influence theory, and self determination theory. Furthermore, information systems practitioners and educators will be able to understand the roles of identity factors in developing and designing TML and KM systems. (Contains 3 tables and 2 figures.)