Transboundary Peace Parks are established along international borders surrounded by biodiversity that needs to be protected, particularly in regions that were devastated as consequence of internal or international conflicts. They are conceived as peacebuilding strategies to bring former enemies together through the joint management of the shared environment. This dissertation explores the effectiveness of Transboundary Peace Parks in promoting more cooperative and peaceful inter-State relations. In order to demonstrate such effectiveness, three initiatives will be analyzed: Cordillera del Cóndor between Ecuador and Peru, the Greater Virunga Transboundary Collaboration between Democratic Republic of Congo (DRC), Rwanda and Uganda and the Balkans Peace Park Project (B3P) involving Albania, Kosovo/a and Montenegro. The concepts State sovereignty, borders and territory will be analyzed in this dissertation since they are key factors to take in account when establishing a Transboundary Peace Park. Apart from States, the involvement of local communities is essential when developing these initiatives. The participation of other stakeholders such as NGOs, international organizations and private donors, is also vital for the success of these initiatives. This dissertation also aims to draw the attention to the positive effects of Peace Parks in their area of influence since they receive mostly criticism.