This article introduces broad strands of research on swearing as a foundation for an interpersonal pragmatics (IP) approach to the nature and effects of swearing in interaction and relationships. The main tenets of interpersonal pragmatics are presented, and swearing as a distinct research focus within IP is outlined. The article invokes pragmatic perspectives in addressing both negative and positive functions of swearing. The central focus on IP is developed by considering the mutual interplay between language and relationships in swearing activity. With respect to communicative context, it is noted that swearing both emerges within interpersonal relationships, and simultaneously provides a context for different types of interpersonal relationships to unfold (endogenous vs. exogenous IP perspectives). By way of introducing the special issue on swearing and interpersonal pragmatics and the constituent articles, it asserts the need to account for swearing as an interpersonal pragmatic strategy and to analyse the causes and effects of swearing in different contexts. The article concludes with a discussion of future research directions, including, in particular, swearing in mediated settings.