Despite its criticality to the success of information system (IS) projects, knowledge sharing among IS projects is generally ineffective compared to knowledge sharing in IS projects. Although several mechanisms for knowledge sharing exist in the literature, it is difficult to determine which mechanism one should use in a specific context. We lack work that concisely and comprehensively classifies these mechanisms. Based on a literature review, we extracted information from 33 studies and identified twelve mechanisms for sharing knowledge among IS projects. Then, we derived a taxonomy for these mechanisms, which extends previous research by both adapting existing mechanisms and complementing the set of dimensions used for their classification. The results help to systematically structure the fields of knowledge management and IS projects. Both research and practice can use this taxonomy to better understand knowledge in this domain and effectively adopt mechanisms for a particular application.