Researchers stress the importance of understanding knowledge transformation in projects. To explore how knowledge is transformed across organizational and specialization boundaries in project networks, we observed 22 knowledge transformation cases in two project networks. We found that new knowledge was created across specialization boundaries and that knowledge was altered across organizational boundaries. When both organizational and specialization boundaries were crossed, new knowledge was created. From these findings, we developed a set of propositions and formulated these into a model of knowledge transformation in project networks. This research contributes to a better understanding of knowledge transformation processes and outcomes in project networks.