© 2019, © 2019 Institute of Muslim Minority Affairs. This article considers the incidence and implications of ¿nikah-only¿ marriages in Ireland, that is, marriages which are conducted according to the rites of the Islamic faith but which do not conform to the legal formalities for marriage under Irish law and thus are not legally recognised. Despite a growing Muslim population in Ireland, little is known about Muslim marriage practice in this jurisdiction and no empirical research on this topic has been conducted to date. Without specific data on the phenomenon of unregistered marriage, this article relies on an examination of the Irish legal formalities for marriage and available statistics on marriage in Ireland to hypothesise about the potential incidence of unregistered Muslim marriages in the jurisdiction. Although the formalities for religious marriage in Ireland are not particularly onerous, it is argued that it is likely that Muslim marriages which do not meet the requirements for legal recognition are occurring. This article will identify some of the legal consequences for couples whose marriage is unrecognised and highlight the need for awareness-raising about Muslim marriage practices in Ireland so that the Muslim community are fully aware of both the significance of seeking legal recognition for their marriages and the challenges inherent in ensuring that their marriage will be legally recognised.