This paper offers a concise overview of the impact made by Scottish evangelicalism of the Free Church of Scotland on the theology, piety and practice of Hungarian Reformed faith within the Austro-Hungarian Empire. They planted a kind of piety that was foreign, at least in its language and expressions, to most of the Hungarian Reformed people until the arrival of Scottish missionaries in 1841. Their conduct of practical Christianity, praxis pietatis materialised itself in Christian evangelism and social action. In this paper the focus is on the period between 1865 and 1914. To demonstrate the nature and form of this impact, first the paper outlines some key features of Scottish evangelicalism. Then, it investigates the theological and ecclesiastical impact of Scottish evangelicalism made through the establishment of voluntary societies and examines influence on the piety and praxis of Reformed faith in Hungary.