Research into workplace bullying has continued to grow and mature since emerging from Scandinavian investigations into school bullying in the late 1970s. Research communities now exist well beyond Scandinavia, including Europe, the UK,Australia, Asia and the USA. While the terms 'harassment' and 'mobbing' are often used to describe bullying behaviour, 'workplace bullying' tends to be the most consistently used term throughout the research community. In the past two decades especially, researchers have made considerable advances in developing conceptual clarity, frameworks and theoretical explanations that help explain and address this very complex, but often oversimplified and misunderstood, phenomenon. Indeed, as a phenomenon, workplace bullying is now better understood with reasonably consistent research findings in relation to its prevalence; its negative effects on targets, bystanders and organizational effectiveness; and some of its likely antecedents. However, as highlighted in this review, many challenges remain, particularly in relation to its theoretical foundations and efficacy of prevention and management strategies. Drawing on Affective Events Theory, this review advances understanding through the development of a new conceptual model and analysis of its interrelated components, which explain the dynamic and complex nature of workplace bullying and emphasize current and future debates. Gaps in the literature and future research directions are discussed, including the vexing problem of developing an agreed definition of workplace bullying among the research community, the emergence of cyberbullying, the importance of bystanders in addressing the phenomenon and the use of both formal and informal approaches to prevention and intervention.