Based on the social exchange theory of Homans, Gouldner, and Malinowski, this sociocultural analysis of three elementary schools focused on principal-teacher and teacher-teacher exchanges of instructional influence. Two questions were asked: (a) In what ways, if any, do principals and teachers in high-achieving, high-poverty schools exchange social influence? and (b) How might these exchanges contribute to a school's instructional capacity? Collected through interview, observation, and document mining, data were analyzed inductively. Two major findings emerged from the data. First, principal and teachers exchanged influence reciprocally through (a) informal prerequisites that created a zone of trust for other exchanges of influence, (b) exchanges initiated by assertive teachers that provided reciprocity and indirect social equilibrium between teachers and principals, and (c) exchanges perceived by all players as instructionally valuable. Second, three processes were analyzed as increasing schoolwide instructional capacity: (a) principal-initiated instructional efforts, (b) teacher-directed instructional initiatives, and (c) principal and teacher access to instructional resources. (Contains 7 tables.)