This article focuses on the works produced in the Iberian Peninsula following the observations of the comets of 1618. It analyzes the astronomical observations conducted in the Iberian kingdoms, distinguishing the work of astrologers from that of philosophers, and examines the mechanisms through which these works achieved widespread publication. While astrologers held distinct perspectives on comets compared to natural philosophers, Iberian authors generally adhered to a conventional Aristotelian cosmology, with one conspicuous exception: Manuel Bocarro Francês, a Portuguese scholar who proposed a Stoic-inspired understanding of comets and the cosmos. Despite their cosmological differences, Iberian astronomers and astrologers unanimously believed that comets exerted a significant influence over meteorological phenomena, human lives, and the course of history. This paper concludes with an analysis of the astrological theories and political eschatology endorsed by the Iberian authors who wrote about the comets of 1618.