The Methodist Episcopal Church was strongly committed to the temperance movement in nineteenth-century America. This commitment rested on assumptions about the negative impacts of alcohol and was expressed through campaigns for personal moral reform and political prohibition. When Methodist missionaries arrived in Singapore in the late nineteenth century, they encountered a society in which opium was the most commonly abused drug. In this new context, Methodist missionaries adapted their concerns about alcohol and their methods of opposing the liquor trade and applied these concerns and methods to opium and the opium trade instead. This case study raises important questions about the inculturation of morality as an aspect of the missionary enterprise, a topic which is insufficiently addressed in literature on theological inculturation. The Methodist Episcopal Church was strongly committed to the temperance movement in nineteenth-century America. This commitment rested on assumptions about the negative impacts of alcohol and was expressed through campaigns for personal moral reform and political prohibition. When Methodist missionaries arrived in Singapore in the late nineteenth century, they encountered a society in which opium was the most commonly abused drug. In this new context, Methodist missionaries adapted their concerns about alcohol and their methods of opposing the liquor trade and applied these concerns and methods to opium and the opium trade instead. This case study raises important questions about the inculturation of morality as an aspect of the missionary enterprise, a topic which is insufficiently addressed in literature on theological inculturation.