The term ‘accommodation theory’ identifies a research program that has developed since the early 1970s, very largely stimulated by the research of Howard Giles and his colleagues. Accommodation theory accounts for diverse contextual processes that impinge on the selection of sociolinguistic codes, styles and strategies and their interactional consequences. In its earliest forms, accommodation theory was a strictly socio-psychological model of speech-style modification, best represented in Giles & Powesland’s (1975) account. Currently, accommodation theory has the status of a truly interdisciplinary model of relational processes in communicative interaction. In the view of some commentators (e.g. Bradac, Hopper & Wiemann, 1989), accommodation theory is the predominant model at the interface of sociolinguistics, communication and social psychology. Studies across the disciplines, from various methodological and ideological perspectives, appear regularly. Recent treatments (see Giles, Coupland & Coupland eds. 1991 for an overview) have begun the task of relating the key explanatory concepts of accommodation theory to local discursive processes in face-to-face interaction, particularly those that relate to achieving solidarity with, or dissociation from, a conversational partner and the social group with which she/he identifies. Extensions of this work could offer pragmatics the means of drawing on a very rich fund of conceptual and empirical data from the social psychology of language and social psychology in general. This article briefly reviews the original concerns of ‘speech accommodation theory’ and traces its progressively broader involvement with communication strategies relevant to both individuals and social groups.