In environmental circles, there are two long-running debates about (1) whether or not indigenous peoples are truly conservationists, and (2) whether or not Christianity is inherently inimical to conservation. In this article, I bring these two debates into dialogue by exploring the changes in resource management practices of an indigenous group in highlands Papua New Guinea, many of whom have recently converted to Christianity. In Porgera, spirits are critical for maintaining and regulating ecological affairs, so it could be assumed that Christianity would erode whatever conservationist principles are extant in traditional religious belief. This is not the case, however. Traditional, conservation-like practices were dependent upon particular spirits, resources, and ecological zones. Christianity has engaged with these spirits, resources, and zones in complex ways. I argue that we need more nuanced understandings of how the global spread of world religions are integrating with traditional resource management practices to more effectively promote sustainability.