This article presents a conceptual review of the literature concerning social work and theory. Based on analysis of 93 research studies, drawn from literature in English published between 1968 and 2016, the review considers the many ways that theory is conceptualised in the literature, and asks meta‐theoretical questions about how and why different conceptualisations arise. The article examines definitional questions and ambiguities concerning the use of theory, extant research on the use of theory by social workers in practice, hostility expressed regarding theory in social work, the theory/practice divide and perspectives that emphasise theory's utility or functionality. The article points at some methodological and ethical limitations concerning current research, and summarises dominant, as well as less prominent, versions of what counts as theory within the social work discipline, before finally suggesting that further meta‐theoretical research is needed.