Systematic literature reviews (SLRs) adopt a specified and transparent approach in order to scope the literature in a field or sub-field. However, there has been little critical comment on their purpose and processes in practice. By undertaking an overview of SLRs in the field of social media (SM) marketing, this article undertakes a critical evaluation of the SLR purposes and processes in a set of recent SLRs and presents a future research agenda for social media marketing. The overview shows that the purposes of SLRs include the following: making sense (of research in a field), developing a concept matrix/taxonomy and supporting research and practice. On SLR processes, while there is some consensus on the stages of the process, there is considerable variation in how these processes are executed. This article offers a resource to inform practice and acts as a platform for further critical debate regarding the nature and value of SLRs.