The purpose of this thesis is to assess how far the Advocacy Coalition Framework (ACF) explains the creation, persistence and radical reform of the Peronist labour regime across two periods: the 1940s-1950s when the labour regime was created, and the 1990s when the persistent labour regime was radically reformed. The thesis pays particular attention to the historical persistence of the Peronist labour regime, and analyses various historical episodes of reform initiatives. The thesis then analyses the contemporary labour domain with particular focus on the reforms and reversal of reforms during 1989-1999 under the governments of Carlos Menem. Much of the literature has highlighted the weakening of Peronist labour regime, particularly in view of the labour market reforms in the early 1990s by the Peronist government of Menem. Yet, the Menem government itself reversed various reforms in the late 1990s, after having spent so much political capital to introduce the reforms, and the Peronist governments of Nestor Kirchner and Cristina Fernandez de Kirchner further restored key components of the traditional labour regime in the 2000s. These experiences raise crucial questions: What explains the significant persistence of the Peronist labour regime? How far does the contemporary Peronist labour policy represent a significant break with the past? How have the main actors shifted their policy positions over time, and how have such changing policy positions interacted with the labour policy process? These questions are also pertinent to theoretical debates as they deal with the three dimensions of policy process: policy persistence, change, and reversal. The thesis deepens the theoretical knowledge also by providing feedbacks about how the Argentine case extends and modifies the ACF itself, such as opening up the ACF to post-modern studies, incorporating discourse analyses, and elucidating the difficulties of centrist groups in playing the role of mediators between coalitions. The thesis also responds to the call in the literature to explore the applicability of the ACF to developing countries and historical cases of non-democratic regimes.