Brain–computer interface (BCI) is a promising technology for restoring communication in individuals with locked-in syndrome (LIS). BCI technology offers a potential tool for individuals with impaired or absent means of effective communication to use brain activity to control an output device such as a computer keyboard. Exploratory studies of BCI devices for communication in people with LIS are underway. Research with individuals with LIS presents not only technological challenges, but ethical challenges as well. Whereas recent attention has been focused on ethical issues that arise at the initiation of studies, such as how to obtain valid consent, relatively little attention has been given to issues at the conclusion of studies. BCI research in LIS highlights one such challenge: How to decide when an exploratory BCI research study should end. In this article, we present the case of an individual with presumed LIS enrolled in an exploratory BCI study. We consider whether two common ethical frameworks for stopping randomized clinical trials—equipoise and nonexploitation—can be usefully applied to elucidating researcher obligations to end exploratory BCI research. We argue that neither framework is a good fit for exploratory BCI research. Instead, we apply recent work on clinician-researcher fiduciary obligations and in turn offer some preliminary recommendations for BCI researchers on how to end exploratory BCI studies.