This report provides a comprehensive overview of the legal and institutional frameworks governing illicit financial flows (IFFs) in Kenya, Ghana, and Tanzania at international, regional, and national levels. It delves into three prevalent forms of IFFs: tax-related IFFs, corruption, and money laundering. It addresses tax-related IFFs arising from aggressive tax planning and evasion, with a focus on the extractive sector in Ghana and Tanzania, although the study in Kenya is not sector-specific. The report then investigates corruption, a significant source of IFFs in all three countries, with a particular focus on the extractive sector in Ghana and Tanzania. Additionally, it examines money laundering in Kenya, emphasizing the banking and real estate sectors. It concludes by discussing the role of civil society organizations (CSOs) in combating IFFs, highlighting the challenges they face, and offering recommendations for effectively addressing these challenges.