PurposeIn successful purchasing relationships, effective communication is a key factor. The purpose of this paper is to explore whether the choice of communication media is affected by different stages in the relationship development process and by different purchasing contexts: product and service purchasing.Design/methodology/approachThe study initially reviews the literature on inter‐organizational communication and purchasing relationships. In order to explore the research question, data were gathered through semi‐structured in‐depth interviews with purchasing managers, buyers and their suppliers in three product and three service purchasing relationships.FindingsThe study identifies a relationship development framework that influences the communication media selection in two purchasing contexts. It confirms that communication media selection is affected by the communication needs of the participants, the stage of relationship development, and the purchasing context.Research limitations/implicationsThis research was limited to six buyer/supplier relationships involving a single multinational buyer organization, so although a range of purchasing contexts was considered, the findings have limited application. The relationship development process and the incidence of media selection should be further examined in varied contexts and a survey of buyers and suppliers should test the framework.Originality/valueThis study is a refinement of the existing predominantly single‐respondent, survey‐based studies in the literature in that both parties in a series of purchasing dyads were interviewed. The paper makes a contribution as it illustrates the application of the media richness theory, explores the contextual factors surrounding media selection and provides a buyer‐supplier relationship development framework based on behavioural and functional aspects of the relationship.