This article reviews ecclesiastical opinions on Indigenous slavery in early modern Chile, the southernmost frontier of the Spanish Empire. Generally, historiography has only analyzed missionary relations with the Mapuche people on the Mapuche-Hispanic frontier. However, the actions by other members of the Catholic Church with regard to Indigenous slavery have received less attention. Therefore, this article reviews how historiography has treated this topic, aiming to cover a larger spectrum of ecclesiastical opinions, discussions, and actions.