Virtue theory is an approach to ethics which emphasizes the character of the moral agent, rather than rules or consequences, as the key element of ethical thinking. This contrasts with consequentialism, which holds that the consequences of a particular act form the basis for any valid moral judgment about that action, and deontology, which derives rightness or wrongness from the character of the act itself rather than the outcomes. The difference between these three approaches to morality tends to lie more in the way moral dilemmas are approached than in the moral conclusions reached. For example, a consequentialist may argue that lying is wrong because of the negative consequences produced by lying — though a consequentialist may allow that certain foreseeable consequences might make lying acceptable. A deontologist might argue that lying is always wrong, regardless of any potential "good" that might come from lying. A virtue ethicist, however, would focus less on lying in any particular instance and instead consider what a decision to tell a lie or not tell a lie said about one's character and moral behavior.

Although concern for virtue appears in several philosophical traditions, in the West the roots of the tradition lie in the work of Plato and Aristotle, and even today the tradition’s key concepts derive from ancient Greek philosophy. These concepts include arete (excellence or virtue), phronesis (practical or moral wisdom), and eudaimonia (flourishing). In the West virtue ethics was the prevailing approach to ethical thinking in the ancient and medieval periods. The tradition suffered an eclipse during the early modern period, as Aristotelianism fell out of favour in the West. Virtue theory returned to prominence in Western philosophical thought in the twentieth century, and is today one of the three dominant approaches to normative theories (the other two being deontology and consequentialism). Virtue theory is not actually in conflict with deontology or teleology as those two viewpoints deal with which actions a person should take in any given scenario, virtue theorists simply argue that developing morally desirable virtues for their own sake will help aid moral actors when such decisions need to be made.

While virtue ethics was born with Plato and Aristotle, their forms of virtue ethics are by no means the only ones. What virtue ethics refers to, rather, is a collection of normative ethical philosophies that place an emphasis on being rather than doing. Another way to say this is that in virtue ethics, morality stems from the identity and/or character of the individual, rather than being a reflection of the actions (or consequences thereof) of the individual. Today, there is a great amount of debate among various adherents of virtue ethics about what specific virtues are morally praiseworthy. However, the one thing they all agree upon is that morality comes as a result of intrinsic virtues—this is the common link that unites the sometimes disparate normative philosophies into the field known as virtue ethics.