The purpose of this paper is to explore how to support active knowledge sharing in online group work which both encourages collaboration and motivates individual effort. In this study, two graduate-level online courses (course 1 and course 2) operated through Blackboard were selected. In both courses, the instructor designed the course activities and online learning environment in a a manner that aimed to promote active group work and knowledge sharing. Sixty students were enrolled in these two courses. Several themes were generalized from the data, which include: (a) community and trust were created for knowledge sharing through multiple course activities; (b) group work shared in blogs stimulated knowledge sharing, interactive learning and learning credibility as well as provided a learning reference for students; (c) transparent group work promoted across-group learning; and (d) progressive and split assignments design with clearly defined components promoted collaboration and satisfied the desire of individual members to work independently.