The aim of this article is to explore where and why religious naturalism differs from its rivals, and also to consider some of the challenges religious naturalism faces. I argue that religious naturalism is best conceived as a reaction against both theists who are religious and naturalists who are atheists: the best option is taken to be a naturalist who is religious. Nevertheless, it is quite difficult to say more exactly what claims the view contains. In fact, it is argued, three forms of religious naturalism must be distinguished and contrasted with their rivals, which are taken to be non-religious naturalism, scientific naturalism, theism (including panentheism), divine transcendentalism, religious agnosticism, and religious relativism.