This article integrates strategic factors influencing trust with social contextual factors to create a broader understanding of interpersonal trust across organizational boundaries. In contrast to more passive models of trust development, it introduces the construct of threat-reducing behavior as an active interpersonal strategy for building and maintaining trust. Using a sample of 207 executive-level boundary spanners working on knowledgebased projects, it finds a positive relationship between threat-reducing behavior and interpersonal trust across organizational boundaries. The study also considers contextual effects by investigating the network density and demographic composition of a boundary spanner's social network of key counterparts from a partner organization. It proposes and demonstrates support for both negative and positive effects of network demographic diversity on trust.