Neurotechnology, traditionally developed for clinical settings for the therapeutic treatment of neurological and sensory-motor disorders, is now expanding into the consumer market, fueled by recent advancements in AI, brain decoding, and sensor technologies. These systems are being employed across diverse sectors—including digital health, wellness, marketing, robotics, communication, gaming, education, and security—with Big Tech players like Meta, which has publicly announced its neural interface wristband, and Apple, which holds a patent for EEG-enabled AirPods, indicating a likely trajectory towards mainstream adoption. While neurotechnologies offer potential social benefits, they also raise critical ethical concerns, around safety, security, privacy, fairness and bias, equity, agency, and misrepresentation. Moreover, this burgeoning field—non-medical neurotechnologies developed for consumer use—remains functionally unregulated. This dissertation makes four key contributions. First, through a narrative review and industry landscape analysis, I provide a foundational overview of the consumer neurotechnology sector, distinguishing it from its clinical and medical origins. Second, through fieldwork and interviews with developers at consumer neurotechnology companies, I uncover on-the-ground conceptions of privacy and the practical strategies practitioners use to address it. Third, I analyze competing philosophical and policy arguments around whether and how consumer neurotechnology should be regulated, specifically with respect to privacy, with an in-depth examination of U.S. laws enacted in 2024. Finally, I situate neurotechnology within a broader trend of machine readability of humans, a phenomenon that raises fundamental questions beyond privacy, including fundamental questions about autonomy.