Since the end of the Cold War, one of the most commonly cited threats to international stability and security has been the existence of pariah or rogue states who actively defy many of the rules and standards of behavior of international politics in an attempt to challenge the legitimacy and general functioning of the international system. Such states pose a significant challenge to the foreign policy of many nations as well as to international law and the organizations that are tasked with enforcing it, most notably the United Nations. While it is well known how such states become designated as pariahs, primarily due to their deviant behavior relative to global norms on things such as nuclear proliferation, human rights, or non-intervention into the internal affairs of other states, it is much less clear how they might be re-socialized into the international community short of a forced military intervention and regime change. What role might these states as well as those that interact with them on a regular basis play in reducing their deviant behavior and helping to improve their national reputations and the stigma and punishment associated with their pariah status? How are members of the international community to know when such nations enact meaningful attempts at removing their pariah designation? To answer these questions, this project proposes a theory of reputational improvement that combines elements of existing theories on reputation with aspects of a growing literature on nation branding and public diplomacy that will show how pariah states might go about improving their reputations and more importantly, convincing others that they are no longer deserving of the designation of being a deviant state. Through careful tracing of the reputational improvement process across three classic examples of pariah states, including South Africa under the Apartheid, Libya under the rule of Muammar Gaddafi, and North Korea under the rule of the Kim regime, this dissertation will show how some attempts at rebranding of a state from pariah to non-pariah are effective at inducing an improvement in national reputation, while others are unsuccessful at eliminating the pariah designation. In addressing this issue, this project adds value to the theoretical understanding of reputation as a public good and tool of public diplomacy as well as provides several policy prescriptions for how the international community might approach existing pariahs to promote their eventual re-socialization into global society.