The Atlas of Religious or Belief Minority Rights is an online tool to map and measure the rights of religious or belief minorities (RBMs) in the European Union countries. Mapping will illuminate what rights RBMs have in each country, and measuring is essential for developing evidence-based policy making. To this end, the Atlas makes use of three indices that measure the promotion of RBM rights (P-index), equal treatment (E-index) and the distance between religious majority and minorities (G-index). The indices have been constructed on the basis of the answers given by national legal experts in response to four questionnaires; their answers have been evaluated using a methodology built with respect to the international standards concerning RBM rights. The Atlas currently covers 12 countries and 13 RBMs. The Atlas’ currently available data focuses on examining and measuring legal systems and soon be supplement with a sociological analysis of the data. Collectively, the Atlas provides new information and data that can help the work scholars, journalists, diplomats, NGOs, and others interested in promoting minority rights.