Key account management (KAM), which involves targeting the largest and most important customers and providing them with special treatment in the areas of marketing, administration, and service, is becoming an important component of many organizations’ marketing strategies. Research suggests that KAM enables the development of close relationships between suppliers and buyers, which, in turn, results in better performance for both organizations. This study examines the influence that core selling teams, a specific KAM strategy, have on supplier–buyer relationships. A model is developed using insights from research on sales and sales management, relationship marketing, and competitive advantage, which explains the influence that core selling teams have on supplier–buyer relationships. The model is tested using data from three sources: (1) self-report data obtained from members of 30 core selling teams of a global consumer products company and their direct (and indirect) managers; (2) data gathered, via personal interviews, from each of the core selling team’s key customers; and (3) objective sales data supplied by the global consumer products company involved in the study.