The study of religion has attracted interest and considerable attention from researchers and practitioners as a result of wanting to know more about religions (such as Islam) and religiosity. However, regardless of the importance of religious studies, religious tourism is still very much under-represented in the literature. In fact, it is distressing to find that little is known about religious tourism in many developed and developing economies. Meanwhile, Islamic tourism (or Halal tourism) is deeply rooted within the Islamic Shari'ah as every Muslim is required to travel for many reasons, some directly related to Islamic Shari'ah itself (e.g. Hajj and Umrah) while many travel for education, medical treatment, and knowledge acquisition, etc. This paper examines the concept of Halal tourism (as a subcategory of religious tourism), its roots, principles and most importantly answers the questions: is Halal tourism really Halal? Is Halal tourism only for Muslim families who abide by Islamic Shari'ah rules? Should it be Halal tourism or Islamic tourism? Is Halal tourism only about Islamic countries or it is also important for other countries? What are the impacts of non-compliance to Halal principles on hotels (and other tourism organisations) performance?