Since the discovery of enterovirus A71 (EV-A71) half a century ago, it has been recognized as the cause of large-scale outbreaks of hand-foot-and-mouth disease worldwide, particularly in the Asia-Pacific region, causing great concern for public health and economic burdens. Detailed mechanisms on the modulation of immune responses after EV-A71 infection have not been fully known, and the lack of appropriate models hinders the development of promising vaccines and drugs. In the present study, NOD-scid IL2Rγ−/− (NSG) mice with a human immune system (humanized mice) at the age of 4 weeks were found to be susceptible to a human isolate of EV-A71 infection. After infection, humanized mice displayed limb weakness, which is similar to the clinical features found in some of the EV-A71-infected patients. Histopathological examination indicated the presence of vacuolation, gliosis, or meningomyelitis in brain stem and spinal cord, which were accompanied by high viral loads detected in these organs. The numbers of activated human CD4+ and CD8+ T cells were upregulated after EV-A71 infection, and EV-A71-specific human T cell responses were found. Furthermore, the secretion of several proinflammatory cytokines, such as human gamma interferon (IFN-γ), interleukin-8 (IL-8), and IL-17A, was elevated in the EV-A71-infected humanized mice. Taken together, our results suggested that the humanized mouse model permits insights into the human immune responses and the pathogenesis of EV-A71 infection, which may provide a platform for the evaluation of anti-EV-A71 drug candidates in the future.