This article proposes a programmatic approach to study nonreligion relationally. "Nonreligion" denotes phenomena that are generally not considered religious but whose significance is more or less dependent on religion (atheists are an obvious example). This approach draws on sociological field-theory to outline how different modes of nonreligiosity result from different configurations of the religious field they relate or are related to, influenced by the cultural and socio-political backgrounds of different societies. Furthermore, modes of nonreligion can be distinguished by differ ent ways of relating to religion. While this relationship is primarily "negative" in some cases, most examples display "positive" characteristics, such as the reference to secular morality through humanism and human rights or the stress of alternative worldviews based on science and naturalism. The article concludes that the diversity of nonreli gion ought to be studied in its own right and on the basis of empirical research that focuses on religious-nonreligious entanglements.