This article examines the ways in which Nonconformist missionary societies worked hand in hand with the British and Foreign School Society (BFSS) to provide them with pedagogic training in the British System and BFSS teaching manuals and resources, as part of their evangelical mission of conversion in the British West Indies, Africa and India in the nineteenth century. The BFSS appealed to Nonconformist missionaries because it was based on unsectarian pedagogy, pioneered by the educationalist Joseph Lancaster. The article explores the various obstacles these missionaries faced, including the religious persecution they experienced in teaching an unsectarian system and the educational difficulties they experienced in persuading parents and local governments of the value of elementary education. It also draws attention to the ways in which they fought race and sex prejudice in the teaching of Africans, slaves and young girls. The current literature on missionary activities in the early nineteenth century pays scant attention to their role as educators: the article reveals the degree of their educational ambition and zeal and the lengths they went to in order to implement a progressive system of unsectarian elementary instruction in key parts of the British empire during the nineteenth century.