Existing explanations of faculty-student interactions emphasize social-organizational characteristics of higher education to the exclusion of social-psychological dimensions of the interactions themselves. Yet, student perceptions are essential cognitive elements that influence frequency of, and growth from, informal interaction with faculty. Drawing on a survey of students at a large public university, this paper expands theoretical understanding of faculty-student interactions by considering how social exchange theory helps explain frequency of, and growth from, informal interactions--and how such patterns vary by social identity.