Epstein-Barr virus (EBV) was discovered 50 years ago as the first candidate human tumor virus. Since then, we have realized that this human γ-herpesvirus establishes persistent infection in the majority of adult humans, but fortunately causes EBV-associated diseases only in few individuals. This is an incredible success story of the human immune system, which controls EBV infection and its transforming capacity for decades. A better understanding of this immune control would not only benefit patients with EBV-associated malignancies, but could also provide clues how to establish such a potent, mostly cell-mediated immune control against other pathogens and tumors. However, the functional relevance of EBV-specific immune responses can only be addressed in vivo, and mice with reconstituted human immune system components (huMice) constitute a small animal model to interrogate the protective value of immune compartments during EBV infection, but also might provide a platform to test EBV-specific vaccines. This chapter will summarize the insights into EBV immunobiology that have already been gained in these models and provide an outlook into promising future avenues to develop this in vivo model of EBV infection and human immune responses further.