The development and delivery of religiously integrated health interventions is increasing, however lack of nomenclature to specify the religious components presents barriers to replication, implementation, and evidence synthesis. We describe the development of the Religious Health Interventions in Behavioural Sciences (RHIBS) Taxonomy, the first scientific classification of religious intervention components to be used globally by chaplains, healthcare providers, and researchers interested in the scientific study of religion, spirituality, and health. We developed a taxonomy of empirically used religious intervention components in health, sought international cross-disciplinary consensus for definitions and tested its usability. Study 1: systematic review of intervention studies to identify religious components tested within healthcare; development of taxonomy nomenclature, definitions, and categories. Study 2: Delphi exercise with 19 international, cross-disciplinary experts from a variety of religions. Study 3: think aloud study and usability testing with 10 end-users. Study 1: 12,337 papers identified from search, 167 intervention studies included, plus an additional 74 from hand-searching 14 systematic reviews. A taxonomy of 191 religious components, grouped into 27 categories resulted. Study 2: two Delphi rounds resulted in international and cross-disciplinary consensus of a revised taxonomy of 81 religious components grouped into 23 categories. Study 3: usability testing by participants (range of disciplines, geography, and religions) led to a final taxonomy comprising 82 religious components grouped into 22 categories and supported by online training. The RHIBS Taxonomy, is the first multidisciplinary, global shared language within religion, spirituality, and health, ushering in a new era for religious interventions to be precisely defined, developed, and tested; shaping the evidence-base for future healthcare research/practice. Lay Summary Currently, religious health interventions are poorly defined and internationally we do not have a shared language that we can use when discussing religious practices. A shared language will help us to understand the different religious practices used. We need this, because we can then find out which religious practices are helpful and which are unhelpful in improving health outcomes. Our project answered the following questions: Can religious practices within health interventions be scientifically classified? Can the classification gain international, cross-disciplinary agreement? Can the classification be reliably and easily used? We found 82 religious practices that have been explored scientifically, we grouped these practices into 22 larger categories to organize and build a classification system that received agreement from international experts from a range of occupational backgrounds. The religious practices have been labeled and defined to make a common language that everyone internationally can share when talking about religious practices in relation to health. The classification system will help to identify and implement the most beneficial religious practices to health and will inform healthcare practice.