Dendritic cells (DC) are critical to the induction and regulation of the innate and adaptive immune responses. They have been implicated in the pathogenesis of many autoimmune and chronic inflammatory diseases as well as contributing to the development of tumours by their lack of appropriate function. As such, understanding human DC biology provides the insight needed to develop applications for their use in the treatment of diseases. Currently, studies on mouse DC outnumber those on human cells; however, the comparison between mouse and human models has been somewhat misleading due to the basic biological and practical differences between the two models. In this review, we summarise the current understanding of human DC subtypes by describing the phenotype of the populations and how this relates to function. We also hope to clarify the differences in nomenclature between the human and mouse models that have arisen by way of the different experimental models.