© Springer Science+Business Media Dordrecht 2015. This chapter outlines two key ethical issues associated with the possible development of brain-computer interfaces (BCIs) for enhancement purposes. Following a brief introduction to brain-computer interfaces, a scenario in which their use for enhancement purposes becomes commonplace is sketched. General ethical issues associated with the widespread adoption of brain-computer interfaces for enhancement are then introduced. The concept of privacy is presented and various issues surrounding this concept are discussed. BCIs are likely to create new challenges in relation to informational privacy and psychological privacy. These challenges are explored, particularly in relation to liberty, autonomy, personal identity, psychological well-being, and safety. It is recommended that the privacy of future BCI users is protected. Following this, the related concept of autonomy is introduced, and various issues surrounding this concept are examined. The manner in which BCIs are likely to impact autonomy is explored, with a particular focus on freedom, brain hacking, and the transfer of autonomy. Due to the moral significance of autonomy, it is recommended that restrictions are placed on the development and availability of certain types of BCIs.