Research shows that one criterion for evaluating the quality of mediation is the inter-personal climate between participants with several variables including "voice". Voice is the opportunity to participate in a process or, more simply put, having a voice in the process. In a mediation process, "voice" could refer to the procedural opportunity available to a party to provide relevant information and to articulate needs and interests in order to achieve a favourable outcome. Research also shows, however, that evaluating the justice quality of a process on the basis of voice may obfuscate unfairness in outcome obtained. This article explores the theoretical underpinnings of "voice" as a measure of mediation justice quality. In doing this, it discusses findings of existing research on the effect of voice on procedural justice as well relevant aspects of mediation theory. Furthermore, it discusses safeguards developed to support voice quality in the mediation process. It concludes that mediation stakeholders need to be aware of injustices that may occur as a result of total reliance on voice as a justice factor in mediation.