In recent years, the relationship between religion and Enlightenment, traditionally cast in opposition to one another, has received increasing reconsideration. Scholars now recognise that even orthodox religion played a central role within the Enlightenment project. This development has marked a paradigm shift in Atlantic world and Enlightenment historiography. However, while the relationship between religion and Enlightenment has been greatly clarified, there remain major gaps in our understanding of the nature and parameters of this relationship. This thesis contributes to the understanding of religion’s function within Enlightenment thought and practice through a case study of the colonial missionary work of the Society in Scotland for Propagating Christian Knowledge (SSPCK). Using primary sources such as institutional records, sermons, journals, diaries and letters, it examines evangelism within the framework of the Enlightenment. The study demonstrates first how both the founders of the SSPCK and the Society’s most fervent advocates of missionary work in the colonies were simultaneously the foremost leaders of the British and American Enlightenment. It then traces the implications of this religious Enlightenment dynamic, illuminating not only the ambitions of the Society’s leadership but also certain contours of intimate encounters between Native Americans, Native Christians and white missionaries. As the SSPCK’s missionary endeavours demonstrate, the relationship between evangelism and Enlightenment not only changed all individuals and institutions involved. It also transformed the very landscape of British Protestant religion. This assessment points to the overarching conclusion that the Enlightenment shaped the very foundation of modern missions. In the process, however, British Atlantic Protestants of many different varieties wove the discourse of the Enlightenment into the tapestry of their understanding of evangelism as a primary means of identity formation, both personally and institutionally. Historiographically, this research forces a reexamination of the nuances of the religious Enlightenment. It also problematizes the static (albeit dominant) interpretation of evangelicalism by observing its emergence in light of the broader conditions of British Atlantic Protestantism.