Amidst the dramatic decline of institutional religion across the West, another development has taken place—what I call the “spiritual turn” [Watts (The Spiritual Turn: The Religion of the Heart and the Making of Romantic Liberal Modernity. Oxford University Press, 2022)]. The spiritual turn is evidenced, first, by the rising number of people who self-identify as “spiritual”, but it is also manifest in the changing character of religion in late modernity—its heightened focus on subjective experience, its expressivism, and its sacralization of individual liberty. Thus, post-1960s liberal democracies are not simply “secular”, they are also significantly “spiritual”. In this chapter, I consider what this means for debates about religious diversity in the twenty-first century. I argue that we should think of the rise of “spirituality” as intimately related to spread of a certain kind of liberalism—what I call romantic liberalism. Put otherwise, “spirituality” and romantic liberalism hold deep elective affinities with one another, such that the spread of the latter tends to breed the spread of the former. Two things follow from this: first, twenty-first century liberal societies are not, and cannot be, neutral toward religions; on the contrary, romantic liberal societies tend to liberalize (or spiritualize) religious traditions, communities, and practices. Thus, romantic liberal societies cannot avoid “taking sides”. Second, non-spiritual forms of religiosity (i.e., conservative forms of religiosity) will very likely feel a sense of threat in romantic liberal societies (indeed, this explains the hostility toward liberalism found on the contemporary “post-liberal” right). In turn, the successful management of religious diversity in twenty-first century liberal societies requires (a) that liberals admit that romantic liberal societies privilege certain forms of religiosity (“spirituality”) at the expense of others, and then work to prevent the stigmatization and demonization of these other religious forms, and (b) that religious conservatives recognize that liberalism, rightly understood, while not neutral, affords more diversity, freedom, and peace than the alternatives.