This article examines Financial Contagion and Regional Spillovers in East African Economies: Post-CPA and Beyond with a focused emphasis on São Tomé and Príncipe within the field of Business. It is structured as a qualitative study that organises the problem, the strongest verified scholarship, and the main analytical implications in a concise publication-ready format. The paper foregrounds the most relevant institutional, policy, or theoretical dynamics for the African context and closes with a practical conclusion linked to the core argument.