The main objective of this dissertation is to analyze Brazil s engagement in the normative debates on international security, especially those that involve the theme of Statebuilding and peacebuilding, as a contestation agent through the construction and practice of the Brazilian Way of Peacebuilding. In order to carry out this analysis, we started with the debate on norms in International Relations to understand how a norm emerges, is consolidated and can be contested. Thus, in order to analyze this normative action in Brazil, we sought to analyze two processes of statebuilding and peacebuilding in which the Brazilian presence is and was quite significant both in military and in political terms: Guinea-Bissau and Haiti. From these cases it was sought to understand how the Brazilian Way of Peacebuilding contests and, in the limit, legitimizes a traditional vision of peacebuilding. Finally, the consequences of these practices for international security norms are presented.