In ethical philosophy, ethical egoism is the normative position that moral agents ought to act in their own self-interest. It differs from psychological egoism, which claims that people can only act in their self-interest. Ethical egoism also differs from rational egoism, which holds that it is rational to act in one's self-interest. Ethical egoism holds, therefore, that actions whose consequences will benefit the doer are ethical.

Ethical egoism contrasts with ethical altruism, which holds that moral agents have an obligation to help others. Egoism and altruism both contrast with ethical utilitarianism, which holds that a moral agent should treat one's self (also known as the subject) with no higher regard than one has for others (as egoism does, by elevating self-interests and "the self" to a status not granted to others). But it also holds that one is not obligated to sacrifice one's own interests (as altruism does) to help others' interests, so long as one's own interests (i.e., one's own desires or well-being) are substantially equivalent to the others' interests and well-being, but they have the choice to do so. Egoism, utilitarianism, and altruism are all forms of consequentialism, but egoism and altruism contrast with utilitarianism, in that egoism and altruism are both agent-focused forms of consequentialism (i.e., subject-focused or subjective). However, utilitarianism is held to be agent-neutral (i.e., objective and impartial): it does not treat the subject's (i.e., the self's, i.e., the moral "agent's") own interests as being more or less important than the interests, desires, or well-being of others.

Ethical egoism does not, however, require moral agents to harm the interests and well-being of others when making moral deliberation; e.g., what is in an agent's self-interest may be incidentally detrimental, beneficial, or neutral in its effect on others. Individualism allows for others' interest and well-being to be disregarded or not, as long as what is chosen is efficacious in satisfying the self-interest of the agent. Nor does ethical egoism necessarily entail that, in pursuing self-interest, one ought always to do what one wants to do; e.g., in the long term, the fulfillment of short-term desires may prove detrimental to the self. Fleeting pleasure, then, takes a back seat to protracted eudaimonia. In the words of James Rachels, "Ethical egoism ... endorses selfishness, but it doesn't endorse foolishness."

Ethical egoism is often used as the philosophical basis for support of right-libertarianism and individualist anarchism. These are political positions based partly on a belief that individuals should not coercively prevent others from exercising freedom of action.