David Boonin has recently advanced several challenges to the self-defense justification of punishment. Boonin argues that the self-defense justification of punishment justifies punishing the innocent, justifies disproportionate punishment, cannot account for mitigating excuses, and does not justify intentionally harming offenders as we do when we punish them. In this paper, I argue that the self-defense justification, suitably understood, can avoid all of these problems. To help demonstrate the self-defense theory’s attraction, I also develop some contrasts between the self-defense justification, Warren Quinn’s better-known "auto-retaliator" argument, and desert-based justifications of punishment. In sum, I show that the self-defense justification of punishment is more resilient than commonly supposed and deserves to be taken seriously as a justification of punishment.