Ethnodoxy is the conceptual linkage of an ethnic group with a particular religion. It has been previously documented in Slavic Orthodox communities. This study uses Arabic-language surveys in Egypt and Morocco to measure this ethno-religious linkage among Arab Muslims. It develops a parsimonious survey scale for measuring ethnodoxy. It also demonstrates that ethnodox and non-ethnodox Egyptians and Moroccans have different political preferences, both for regime type and for the role of religion in politics