Prior work suggests that mutual trust is an important antecedent to knowledge transfer and shared understanding between the IS and business units; however, the findings have been based on a conceptualization of trust as a one-dimensional construct. Using a richer dyadic conceptualization and operationalization of trust, we empirically investigated the degree to which the importance of trust varies across two members of a dyadic relationship as well as the different role of distinct facets of trust. Analysis of data collected from two informants (the IS manager and a business-unit counterpart) in a sample of manufacturing firms showed that perceived business-unit trustworthiness was significantly more important in fostering shared business–IS understanding than perceived IS-unit trustworthiness. We attributed this to the inherent power asymmetry that characterizes the relationship between IS and business units. We further hypothesized and found that the importance of the three key dimensions of trust (benevolence, integrity, and competence) depended on the relationship age and organizational position of the IS unit. Our findings show how to manage this critical dyadic relationships more effectively and also where to focus trust-building practices in order to ensure success