Do Muslims and Christians worship the same God? We answer: it depends. To begin, we clear away some specious arguments surrounding this issue, to make room for the central question: What determines the reference of a name, and under what conditions do names shift reference? We’ll introduce Gareth Evans’s theory of reference, on which a name refers to the dominant source of information in that name’s “dossier,” and we then develop the theory’s notion of dominance. We conclude that whether Muslims’ use of “Allah” co-refers with Christians’ use of “God” depends on how much weight is given to what type of information in the dossiers of these two names, and we offer a two-part test by which the reader can determine whether Muslim and Christian uses of the divine names co-refer: If Christianity were true and Islam false, might “Allah” still refer to God? And: If Islam were true and Christianity false, might “God” still refer to Allah? We explain the implications of your answers to those questions, and we close with a few reflections about what, in addition to reference, might be required for worship, and whether, from a Christian perspective, salvation turns on this issue.