This article examines the Society in Scotland for Propagating Christian Knowledge (SSPCK) and its missions in the Highlands and Britain's American colonies. Constituted in 1709 and operating as an auxiliary arm of the Church of Scotland, the SSPCK aimed to extend Christianity in ‘Popish and Infidel parts of the world’. It founded numerous Highland charity schools, and from 1729 sponsored missions to Native Americans in New England and Georgia. Missions were increasingly important in British overseas expansion; consequently, historians have viewed the society as a civilizing agency, which deployed religious instruction to assimilate ‘savage’ heathens into the fold of Britain's empire. This article suggests that the SSPCK was equally concerned with Christianization: missionaries focused on spiritual edification for the salvation of souls, indicating a disjuncture between the society's objectives and the priorities of imperial expansion. It also challenges the parity assumed by historians between the SSPCK's domestic and foreign missions, arguing that the society increasingly prioritized colonial endeavours in an attempt to recover providential favour. In doing so, it sheds new light on Scottish ideas of mission during the first half of the eighteenth century, and reassesses the Scottish Church's role in Britain's emerging empire.