Secular worldviews are widespread and growing. What are the differences between secular self-identifications? This study examined if self-identified atheists, agnostics, and humanists differed systematically with regard to worldview dimensions. Cultural and gender effects were examined as secondary study objectives. A total of 1,814 nonreligious individuals from Germany, Austria, and the Netherlands completed questionnaires measuring degrees of atheism, agnosticism, humanism, personal responsibility, scientism, economic materialism, skepticism, dogmatism, existential search, and concealment and disclosure of convictions. As expected, self-identified atheists, agnostics, and humanists differed substantially in their worldview positions and communication. Across all three countries, atheists endorsed atheism to a very high degree. Compared to agnostics and humanists, they were more convinced of scientism and less of skepticism. Agnostics scored highest in agnosticism and skepticism and lowest in dogmatism. Humanists mostly held distinguishable middle positions between atheists and agnostics. Analyses of cultural differences supported the hypothesis that more religious contexts give rise to secular countermovements: In (more religious/less secular) Austria and Germany, atheism, scientism, personal responsibility, and disclosure were more pronounced than in the (secular) Netherlands, where agnosticism and skepticism were more prevalent. Regarding gender, men scored higher on atheism and scientism, and women on skepticism. The findings suggest a continuum from decided to open secularity, two clearly distinct positions. Decided (atheist, scientist, disclosing) secularity was more common among self-identified atheists, men, and in more religious contexts. Open (agnostic, skeptic) secularity was more prominent among self-identified agnostics, women, and in the more secular culture. Self-identified humanists occupied a middle position.