The aim of this dissertation is to explore the macroeconomic implications of a popular idea in the post-growth literature, namely that the global North should start a post-growth transition first to allow ecological space for the development of the global South. A 2-region post-Keynesian stock-flow consistent model has been developed to carry out this analysis in a North-South context. The model is theoretical and simulates two growing economies with free capital movement and a fully flexible exchange rate. In this work, the initial narrative is replicated by assuming that the Northern region, representing the developed world, starts a post-growth transition by targeting a net reduction of its material footprint. The policy introduced to achieve such a goal is a cap on resources that becomes progressively smaller in every period. At the same time, the other region, which is dubbed the ‘South’ and represents the developing world, continues its pursuit of economic development. This central narrative is elaborated throughout the dissertation by assuming different levels of cooperation between the two regions. The results of the analysis show that a non-cooperative post-growth transition in the North triggers a balance of payments crisis in the South, which results in a financial and economic crisis for the latter. If cooperation is introduced in the form of a financial and technology transfer from the North to the South, the macroeconomic outcomes of the South improve substantially. However, the ensuing Southern economic development increases the consumption of resources at the global level, frustrating the efforts towards sustainability of the North. The dissertation concludes by stressing the importance of allowing financial space for the development of the global South, while highlighting that the ecological space left by the global North is unlikely to be sufficient to allow for the sustainable development of the global South without further action in the South to reduce environmental impact.