As more and more organizations are reaching the limits of their internal innovation performance, they are increasingly forced to seek external innovation opportunities through inter-organizational collaboration forms, such as creative projects. These collaborations require both efficient and effective forms of communication since a common understanding is required for success. Differences in knowledge backgrounds hinder the collaboration of multiple stakeholder groups by making knowledge integration difficult, especially when they collaborate for the first time. Boundary objects are attributed a mediating capability. While design artifacts are often used to facilitate communication, their value in promoting multi-stakeholder collaboration is not yet fully understood. Addressing the gap, we analyze when artifacts turn into boundary objects and how they promote interaction between stakeholder groups. Building on the results of an in-depth case-study, we illustrate the insights that boundary objects provide for stakeholder integration. After discussing these insights, we outline directions for future research and practice.