Respiratory syncytial virus (RSV) is the leading cause of serious lower respiratory track illness causing bronchiolitis and some mortality in infants and the elderly. Despite decades of research there is no licensed RSV vaccine. To enable the development of RSV vaccines, several major obstacles must be overcome including immature and waning immunity to RSV infection, the capacity of RSV to evade immunity and the failure of RSV infection to induce robust enduring immunity. Since the failure of the formalin-inactivated RSV vaccine trial, more cautious and deliberate progress has been made toward RSV vaccine development using a variety of experimental approaches. The scientific rational and the state of development of these approaches are reviewed in this article.