From epileptic seizures to depressive symptoms, predictive neurotechnologies are used for a large range of applications. In this article we focus on advisory devices; namely, predictive neurotechnology programmed to detect specific neural events (e.g., epileptic seizure) and advise users to take necessary steps to reduce or avoid the impact of the forecasted neuroevent. Receiving advise from a predictive device is not without ethical concerns. The problem with predictive neural devices, in particular advisory ones, is the risk of seeing one’s autonomous (...) choice supplanted by the predictions instead of being supplemented by it. For users, there is a potential shift from being assisted by the system to being over-dependent on the technology. In other terms, it introduces ethical issues associated with epistemic dependency. In this article, we examine the notion of epistemic authority in relation to predictive neurotechnologies. Section 1 of our article explores and defines the concept of epistemic authority. In section 2, we illustrate how predictive devices are best conceived of as epistemic authorities and we explore the subject-device epistemic relationship. In section 3, we spell out the risk of harms interconnected with epistemic deferral. We conclude by stressing a set of preliminary measures to prepare users for the authoritative nature of predictive devices. (shrink)