It was once believed to be axiomatic that modernisation inevitably leads to religious privatisation and secularisation. As a result, there would be a fundamental, global decline in religion’s social and political importance. This was believed to be the case, regardless of religious tradition or form of political power dominant in the context in which religion found itself. The 1979 revolution in Iran posed fundamental questions in relation to this conventional wisdom. Contemporaneously, the Roman Catholic Church began to play an increasingly important role in relation to democratisation in Central and Eastern Europe, Africa, East Asia and Latin America. These two developments not only collectively emphasised that modernisation does not always leads to secularisation but also that religion can sometimes play a fundamental role in issues of political representation and legitimacy. Contrary to the secularisation theory, there has been a widespread – some say, global – resurgence of religion, often as a political actor in numerous countries. This has involved various religious traditions. Overall, it emphasises not only that there is more than one relevant interpretation of modernisation but also that religion can and does play a role in political changes, even in parts of the world, including Europe, that has been long regarded as inevitably secularising. The paper examines the role of religion in the third wave of democracy and its aftermath, including the 'Arab Spring'