The potential influence of perceived popularity of political parties or candidates on individual vote choice is most commonly studied in terms of a ‘bandwagon effect’. However, there is confusion over exactly what the bandwagon effect is. In this article, I seek to remedy this confusion by providing a clear definition and typology of bandwagon effects, grounded in a review which reappraises existing scholarship. I argue that the bandwagon effect is a distinct social phenomenon involving an individual-level change in vote choice or turnout decision towards a more or increasingly popular candidate or party, motivated initially by this popularity. I then break this down employing a typology which draws on distinctions made in the literature between static and dynamic, and conversion and mobilisation effects. This conception of the bandwagon effect leaves it open to the operation of a variety of possible underlying processes. Scholars should apply such clear concepts as are proposed here in bandwagon research, to situate and clarify their contributions theoretically and offer a more nuanced understanding of whether, how and why bandwagon effects occur across different political contexts.