This entry critically examines the ethical and leadership implications of the Ring of Gyges myth as presented in Plato’s philosophical masterpiece, The Republic, Book II. The myth represents an engaging commentary on the nature of ethics and its significance for social behavior and leadership development. Additionally, the myth of Gyges highlights the tension between the psychological underpinnings of external accountability and internal moral imperative; the perils of unbridled, unchecked power; and the role of moral psychology in leadership development. The entry contends that true (ethical) leadership stems from a high internal moral compass. It demands a deeper commitment to justice (righteousness) that transcends societal scrutiny, rooting itself in abiding integrity, unimpeachable conscience, and objective moral reasoning. The myth is a powerful reminder of how, in absence of the guiding light of a strong internal moral compass, any leader with unchecked power can succumb to, and rationalize, unethical behavior when accountability is removed (as with invisibility). Finally, it will discuss some modern interpretations and applications of the Ring of Gyges and their relevance to Socratic virtue ethics. Using the Ring of Gyges as a broad template, this article summarizes the classic scholarly debate on virtue ethics, as presented in Plato’s Republic, about whether justice “pays” intrinsically or instrumentally or both; and how true human flourishing is predicated on moral virtue. This discussion has engaging relevance and important lessons for modern times, where many leaders seem to have lost their moral bearings. In sum, this entry contends that true ethical action must be rooted in internal virtue and not external enforcement or consequences. Only then it can result in the wise use of power by the leaders.