This article examines how employee voice is understood by both scholars of labour law and of industrial relations. While there is a sophisticated literature on employee participation and involvement in employment relations scholarship, there is an absence of consideration of legal perspectives. The article addresses this gap in the literature by first examining how employee voice is used to explain and critique workplace practices in the dominant and emerging employment relations scholarship, and then critically considering how dominant legal theories refer to and confine understandings of employee participation. The article examines each field through its discipline, method, approach, content and limits. It concludes that the scope of these disciplines is very different, and that they might be regarded as fraternal rather than identical twins. Finally, some questions are raised about the challenges for research in developing an interdisciplinary scholarship of employee voice.