Abstract: This essay contrasts two approaches to permissible self-defensive killing. The first is the forfeiture approach; the second is the elbow room for self-defense approach. The forfeiture approach comes in many versions — not all of which make prominent use of the word “forfeiture.” However, all versions presume that the permissibility of X killing Y (when X must kill Y in order to prevent herself from being unjustly killed) depends entirely on there being some feature of Y in virtue of which Y has become liable to be killed, that is, in virtue of which Y has forfeited or lost or been stripped of his right not to be killed. Different versions of the forfeiture approach advance different claims about what feature of Y will render Y liable to being killed by X. I criticize versions of this approach offered by Thomson, Otsuka, and McMahan and argue that the shared deep error is the presumption that the permissibility of X’s action turns entirely on some feature of Y. In focusing entirely on Y, the forfeiture approach fails to take seriously X’s right of self-defense. In contrast, the elbow room for self-defense approach starts with an explication of a plausible right of self-defense and maintains that a proper explication of Y’s right not to be killed must make moral elbow room from X’s exercise of this right. Within the elbow room approach, Y’s liability to being killed is based upon X’s right of self-defense rather than the permissibility of X’s killing Y being based upon Y’s forfeiture.