Knowledge sharing has been widely discussed in previous literature of knowledge management, as it is regarded as an effective approach for organizations to leverage their knowledge assets and achieve competitive advantages. Particularly, much effort was given to the study of knowledge sharing systems in IS research due to the promising role of information technology in this area. However, little research was done to investigate the knowledge sharing from the behavioral perspective of individuals. With three survey-based studies, the present research investigated respectively the perceived importance of various factors to knowledge sharing behavior, the influential variables of individuals' attitude towards knowledge sharing, and the enhancing effect of knowledge sharing behavior on individuals' intrinsic motivation towards their work. These three studies provide us with a preliminary understanding about why people intend to share knowledge with others, and how knowledge sharing can benefit an individual psychologically and enhance organizational performance. Implications for academic research and practical applications are also discussed in each of the studies. Keywords: knowledge sharing, knowledge management, attitude, intrinsic motivation.