This chapter explores some of the connections between religious diversity and theism, beginning with a brief review of the scope and meaning of the terms “religion” and “religious diversity.” A discussion of why religious diversity is sometimes thought to be problematic prepares the ground for a look at some of the ways in which it has been deployed within arguments for atheism or agnosticism. After outlining some possible responses to these arguments, attention turns to religious pluralism–a theory that, in various forms, is widely held today. The chapter closes by shifting focus from the mooted problems diversity raises for theistic belief and, instead, suggests some reasons why we might find religious diversity valuable.