Buyer-supplier relationships and the interaction betweenthe two parties have long been a popular topic of industrialmarketing and purchasing. Despite the rich body ofliterature on the related topics, special focus on processbasedrelational view could be a new perspective whichfinally might lead to new findings. The purpose of thispaper is to develop a process-based framework for buyersupplierinterfaces from a dyadic perspective, which isbased on the interaction approach of Industrial Marketingand Purchasing Group (IMP), and complemented bytransaction cost theory. It is argued that the sourcingprocess and the marketing process on each side of thebuyer-supplier interface are interactive, where each step ofthe processes is being done in sync. This interaction is thenilluminated, with focus on the sourcing process from thebuyer side. The paper integrates the relational view into theinvestigation of sourcing process, discusses the interactionalong a commonly defined sourcing process, and derivespropositions concerning the strategic interaction,interaction degree and impacts of buyer-supplierrelationships on the sourcing process.