In recent decades much has been written about the role of sectarianism in Middle East politics and there is general recognition that there has been some kind of sectarian surge at the regional level. However, most research has focused on the obvious places where one finds either open conflicts with a clear sectarian dimensions (such as in Syria, Iraq, and Bahrain) or other places where the population is mixed (such as in Lebanon, Saudi, and Kuwait). Far less attention has been directed to the question about whether and how regional sectarianism has also had an impact on less likely places; e.g. countries with neither open sectarian conflict or mixed populations. This paper aims to address this gap in the knowledge about the role of sectarianism in current Middle East politics through a case-study of Jordan. The Jordanian case is especially compelling, because it has no significant Shia population, yet our research shows signs of rising anti-Shia sentiment at multiple levels: government, opposition (both Islamist and secular), and even in intra-Islamist discourse (between the Muslim Brotherhood and rival Salafi forms of political mobilization, for example). Yet the notion of ‘sectarianism’ in Jordan has historically been interpreted in intra-ethnic terms in the form of Jordanian-Palestinian fissures, not in Sunni-Shia terms. Finally, the Jordanian state – and the Hashemite regime specifically – has long supported inter-faith cooperation efforts and campaigns for religious tolerance. Yet the same state is also associated with warnings, as early as 2003, of a “Shia crescent”. So should Jordan be seen as a force for or against rising sectarianism? And to what extent has sectarianism increased in, or affected, Jordanian domestic politics? These are the key questions that gave rise to the current research project. Based on field work, interviews, and a workshop with leading Jordanian analysts, this paper examines to what extent, and in what ways, regional sectarianism has emerged even in Jordanian domestic politics, at both government and opposition levels, and what this means for the Hashemite Kingdom and the region at large. We argue, in our conclusions, that the pre-2011 data suggest an elite-driven, top-down, type of sectarianism that ultimately had little resonance within Jordanian domestic politics. But, perhaps ironically for the regime that coined the term “Shi’a Crescent”, the post-2011 evidence suggests almost the opposite: bottom-up or socially-driven forms of sectarianism that have had far greater resonance, affecting regime and opposition alike.