In academia and the media, a growing interest in people claiming to live “without religion” has emerged in recent years. In the last decade, many scientific studies and public opinion texts on this social group have appeared, mostly establishing an analogy with the dominant narratives of secularization or modernization. Since the 1990s, several surveys have highlighted the quantitative growth of people “without religion” and resulted in an intensification of interest in this social group, further stimulating the assumption that there is a deep relationship between people “without religion” and secularisation. In Portugal, people “without religion” already represent the second largest group of the total population. However, the assertion of “without religion” is sociologically ambiguous. A closer look at the people “without religion” reveals that this category encompasses a wide range of different positions. Nevertheless, the declaration “without religion” does not necessarily mean "nonreligious" or living without a certain transcendent horizon. This seminar provides a sociological approach to the category of people “without religion”, identifying in more detail (and in a historical perspective) the heterogeneity of this phenomenon.