The impact of unexpected changes in new product development (NPD) project scope on the performance of project teams cannot be overlooked in today’s complex business environment in which project owners’requests and expectations change constantly. The results of a recent literature review indicate that successful knowledge sharing practices can lead to the development of competitive advantages of a project team by enhancing individuals’abilities of coordination and problem solving. On the other hand, undesired consequences may occur if the knowledge cannot be effectively shared among the team members. Nevertheless, there have been very few studies engaging in exploring the knowledge sharing mechanisms used and the contingency factors affecting the application of these mechanisms in the context of NPD projects with unexpected change in scopes. Consequently, in this study the knowledge sharing mechanisms used by project teams and the contingency factors affecting the use of these mechanisms when encountering changes in the NPD project scopes are explored by conducting an in-depth case study. The findings can help NPD project teams examine their abilities to harness critical knowledge, and, in turn, develop effective methods to share it in order to enhance NPD project performance.