This book explores two kinds of universalist thought circulating among Jews in the Greco-Roman world. The first, which is founded on the idea that all people may worship the One True God in an engaged and sustained manner, originates in biblical prophetic literature. The second, which underscores a common ethic that all people share, arose in the second century bce. This study offers one definition of Second Temple Jewish universalism that applies to both of these types of universalism: universalist literature presumes that all people, regardless of religion and ethnicity, have access to a relationship with the Israelite God and the benefits promised to those loyal to this God, without demanding that they participate in the Israelite community as a Jew. In texts that employ the Universalized Worship model, the distinguishing aspects of Judaism are acknowledged, while in texts that employ Ethical Universalism, these aspects are absent. The first section of this book explores four types of relationships in biblical prophetic literature between Israelites and non-Israelites: Israel as Subjugators, Israel as Standard-Bearers, Naturalized Nations, and Universalized Worship. All four of these models envision a time in which the foreign nations will acknowledge God, but it is only the Universalized Worship model that offers a truly universalist vision of the end-time. The second section of this book studies how these four models are employed in post-biblical Second Temple literature, and the third section studies late Second Temple texts that employ Ethical Universalism. This study closes with the suggestion that Ethical Universalist ideas expressed in late Second Temple texts reflect exposure to Stoic thinkers who were developing universalist ideas in the second century bce.