An exposition of the moral philosophy of Kant, Arendt and Mill Immanuel Kant adheres to deontological ethics. His theory offers a vision of morality based on the principle of good will and duty. According to him, people can perform good actions solely with good intentions, without any consideration of the consequences. Furthermore, one must follow the laws and the categorical imperative to act in accordance with and with respect to duty. Many other philosophers, such as Hannah Arendt, discuss Kant's moral philosophy. In her case study, “The Accused and the Duties of a Law-Abiding Citizen,” Arendt examines how Adolf Eichmann's actions conformed to Kant's moral precepts but also how they conflicted with his conception of duty. In contrast, John Stuart Mill takes a teleological view of moral philosophy. He expounds his view of consequentialism and utilitarianism to argue that an action is morally right only to the extent that it maximizes the overall happiness of all parties involved, regardless of the motive. In this article I will expose Kant's moral precepts and the importance of duty in his deontological principles. Next, I will evaluate Arendt's report on Adolf Eichmann to analyze the ways in which his actions conformed to or ran counter to Kant's moral philosophy. I will conclude my discussion with an evaluation of Mill's approach to morality to examine the differences between his teleological philosophy and Kant's ethical principles. Kant's moral philosophy is based on the categorical imperative (CI), good will and duty. According to the IC it is an absolute necessity, a command that human beings must conform to universalizable maxims, treat people as ends in themselves, and exercise their will without any concern for the consequences or conditions of their actions... .... middle of paper......The three philosophers all have different ways of analyzing and perceiving ethical principles. They all base their opinions on different concepts of morality. Kant's deontological ethics is based on the concepts of duty, categorical imperative and good will. Similarly, Arendt uses Kant's categorical imperative and the idea of ​​duty to share her account of the trial of Adolf Eichmann. He recognizes that although Eichmann attempted to live by a Kantian definition of duty, his behavior did not fit Kant's moral precepts. Mill, on the other hand, advocates a teleological philosophy and uses the concept of consequentialism and utilitarianism to argue against Kant's morality. In any case, the three philosophers bring thoughtful ethical-philosophical concepts that provide new ways to analyze moral conflicts.