The differences between the statutory formalities required for entry into a legally recognised marriage in many common law jurisdictions and traditional Muslim marriage practice have given rise to doubts as to the legal status of a potentially significant number of Muslim marriages undertaken in the Western World. Although much of the discussion in recent times has focused on the civil recognition of Muslim marriages in England and Wales, the issue is by no means confined to that jurisdiction. Islam is now the third largest and one of the fastest growing religions in Ireland. In this context, and informed by available (albeit limited) data on Muslim marriage practice in Ireland, this chapter explores whether, or to what extent, non-state registered marriages – so called nikah-only marriages – may be taking place within the jurisdiction.