This book engages contemporary debates about the notion of secularism outside of the field of education in order to consider how secularism shapes the formation of progressive sexuality education. Focusing on the US, Canada, Ireland, Aotearoa-New Zealand and Australia, this text considers the affinities, prejudices, and attachments of scholars who advocate secular worldviews in the context of sexuality education, and some of the consequences that ensue from these ways of seeing. This study identifies and interrogates how secularism infuses progressive sexuality education. It asks readers to consider their own investments in particular ways of thinking and researching in the field of sexuality education, and to think about how these investments have developed and how they shape existing discourses within the field of sexuality education. It hones in on how progressive sexuality education has come to develop in the way that it has, and how this relates to conceits of secularism. This book prompts a consideration of how "progressive" scholarship and practice might get in the way of meaningful conversations with students, teachers, and peers who think differently about the field of sexuality education.