Increasingly, universities and school districts share responsibility for teacher and student learning. Sharing responsibility demands that both institutions work to develop closer relationships through ongoing engagement, dialogue and negotiation. Drawing from Cultural Historical Activity Theory (CHAT), we examined one school/university partnership to identify potential barriers to the close relationships that shared responsibility demands. We illustrate these barriers from the point of view of university-based site faculty, recognizing that a full understanding requires multiple perspectives. However, our study offers useful insights about the work and tensions that merge for individuals who serve in boundary crossing roles when two communities with different core missions engage in a common activity intended to produce mutual benefits. We offer some recommendations to anticipate and reduce barriers to active, engaged school/university partnerships.