Despite the popularity of arming rebels as a foreign policy option, there is very little, if any, detailed engagement with the ethical issues surrounding the practice. There is a growing literature on the ethical issues surrounding civil wars and, more specifically, the conditions for engaging in just rebellion; but the focus of this literature is largely on the question of the justifiability of the rebels themselves in engaging in civil war and their conduct when doing so, rather than the permissibility (...) of the arming of rebels by other agents. It is precisely this issue that I want to address here. Overall, I argue that the process should be generally eschewed. More specifically, this article seeks to establish that arming rebels is generally impermissible and only exceptionally morally permissible. The former, far more restrictive claim will be established in the first part of the article. The latter, more permissive claim will be established in the second part of the article. (shrink)