At first blush, Montesquieu seems to exemplify a typical Enlightenment attitude towards revealed religion. Nevertheless, as I argue in this chapter, Montesquieu did not just promote a critical, irreverent attitude to religious dogma and practice. While subtly undermining the idea that Christianity was the one true religion in his masterpiece, The Spirit of the Laws, he at the same time developed an original defense of established religion in general, and Christianity in particular, on instrumental grounds, as being socially and politically useful. Taking account of this aspect of Montesquieu’s work sheds new light on a topic that has provoked considerable scholarly discussion: the diversity of enlightened attitudes towards religion. In particular, my analysis of Montesquieu’s views on religion helps bring into focus a particular strand of Enlightenment thinking that has hitherto remained unacknowledged in the literature and that we might describe as the “Complacent Enlightenment”.