This chapter is concerned with religious soft power in foreign policy making through a focus on the foreign policies of the USA, India and Iran. It suggests that, if religious actors ‘get the ear’ of key foreign policy makers because of their shared religious beliefs, the former may become able to influence foreign policy outcomes through the exercise of religious soft power. In relation to the above-mentioned countries, the chapter proposes that several named religious actors do significantly influence foreign policy through such a strategy. It also notes that such influence is apparent not only when key policy makers share religious values, norms and beliefs but also when policy makers accept that foreign policy should be informed by them. This chapter argues that religious soft power in foreign policy making warrants further research by highlighting the existing treatment of religion’s soft power in the secondary literature to propose a new research agenda. Although many authors attest to the significance of religion in international relations – with some observers noting a recent widespread religious resurgence – there is less agreement on how religion affects foreign policy (Fox and Sandler, 2004; Norris and Inglehart, 2004; Thomas 2005; Haynes 2007a).1 This chapter is not concerned generally with religious soft power in international relations. If that were the focus then the emphasis would be on religious actors in one country seeking to use soft power to influence individuals or groups in another country. For example, various kinds of religious missions – notably, Christian and Muslim – have for centuries been a key expression of international religious soft power. Their aim is to seek to change people’s religious norms, values and beliefs from one set of views to another set; the result is that individuals and groups in a foreign country eventually behave religiously like the original proselytizers.