Nepal's greater one-horned rhinoceros (Rhinoceros unicornis) faces serious threats from poaching. Poaching of these rhinos is a complex problem, influenced by such diverse factors as the price of rhino horn on the international market, local socioeconomic factors, and the population dynamics of the species. Few studies have attempted to address this complexity. In this study, we model the poaching and population dynamics of the one-horned rhinoceros within an integrated framework of ecological, socioeconomic, political, and legal dimensions. The poaching model for rhinos in Royal Chitwan National Park (RCNP) in Nepal is combined with the population model for the species within a simulation framework and explored under various alternative policy scenarios with differing external socioeconomic and political conditions as well as internal policy response. We predict that, under the current (2003–2005) rhino conservation strategy, poaching would continue to be a major threat to the rhino population in RCNP. Furthermore, the internal policy response must begin to consider external factors such as socioeconomic conditions within the park buffer zone to be more effective in the long run. Finally, we find that, for long-run control, antipoaching policies should be directed at increasing the opportunity costs of poaching by creating better alternative economic opportunities, and at antipoaching enforcement.