Engineering project networks are increasingly global in scope and outsourcing is increasingly common. Along with globalizing trends in project delivery, the workforce is also globalizing. It is common for engineers to move to other countries as expatriate workers or as emigrants to pursue job opportunities in other firms. Where much is known about global networks of engineers collaborating on projects, little is known about the mediating role played by individuals that share the same nationality as an international partner on a project. In this paper, we examine two project teams executing complex, reciprocally interdependent design projects in India. One team was comprised of Indians and Americans. The other team was identical, but also contained an Indian national who had studied and worked in the United States. Both teams worked on similar design schedule optimization problems. Over the duration of three days, we examined the interactions of the teams assembled to finalize their designs. Through quantitative network analysis and qualitative observations of the cross-cultural interactions, we found the Indian expatriate to play a cultural boundary spanning role resolving cross-cultural knowledge system conflicts and increasing collaboration effectiveness. We induce a propositional theoretical model of cultural boundary spanning in global engineering project networks.