The claim that virtue requires self-knowledge may seem banal, but it has been challenged by recent claims that certain virtues, such as modesty, require ignorance of self and that self-deceived persons are both happier and nicer. My argument is grounded in a broadly Aristotelian conception of virtue, where full moral virtue includes both the virtues of character, such as temperance, generosity, and courage, and the intellectual virtue of practical wisdom. I argue that self-knowledge is necessary for practical wisdom and practical wisdom is necessary for virtue; hence, self-knowledge is necessary for virtue. However, self-knowledge is not sufficient for virtue, as a person could lack other capacities or insights that would enable her to act ...