The inquiry examines how denial of the ancient gods was envisioned and reported in classical antiquity, adopting a working definition that treats atheism as denial of the traditional deities rather than later philosophical notions of God. It traces how the term functioned in both moral censure and philosophical discourse, surveys philosophers and schools who questioned or explained away popular gods, and discusses borderline positions that reinterpret rather than reject divine beings. Emphasis falls on the relative rarity of uncompromising denial, methodological problems in the sources, and the implications of dissenting views for understanding the resilience of popular religion.