Understanding conceptual modeling, assessment and establishment of interorganizational trust in collaborative networks is challenging. Traditionally, the concept of trust has been addressed at the individuals' level. It is also mostly assumed to be a phenomenon that naturally emerges rather than being created. However, today the concept of trust has become an amenable factor for smoothening inter-organizational collaboration and thus has raised the need to address trust from a new angle. However, the traditional approaches and mechanisms for both assessing the trust level of individuals and/or applying such results for creation of trust are inadequate for analyzing interorganizational trust. This chapter contributes to the support for understanding the concepts and needs of trust among organizations involved in collaborations. The chapter characterizes inter-organizational trust, presents three modeling formalisms for trust and exemplifies them with some trust models that can be applied for different purposes related to interorganizational trust in Virtual organization Breeding Environments (VBEs).