Tax crimes, corruption, terrorist financing, money laundering, and other financial crimes threaten the strategic, political, and economic interests of all countries. The sums lost to illicit financial flows (IFFs), including those that derive from these crimes are vast. For example, a 2011 UNODC report estimates that from 2000 to 2009, total proceeds from transnational organised crime was the equivalent of 1.5% of global GDP, or USD 870bn in 2009. These illegal activities and ensuing lost revenues complicate efforts to reach the Sustainable Development Goals (SDGs) and meet the objectives of the 2015 Cebu Action Plan such as good governance, sound fiscal policies, and infrastructure financing. These crimes are all closely related and thrive in a climate of secrecy, inadequate legal frameworks, lax regulation, poor enforcement, and weak inter-agency co-operation. By exploiting these weaknesses and advances in technology, criminals can covertly move substantial sums between multiple jurisdictions with relative ease and great speed. Consequently, criminal activity and the illicit financial flows that follow are becoming ever more sophisticated. Meanwhile, law enforcement structures have, in many cases, not evolved at the same speed and the international community has struggled to keep up with this threat. In recognition of the importance of this topic, APEC Finance Ministers included in their Cebu Action Plan a roadmap for a more sustainable financial future for the Asia-Pacific region. Specifically, Action item 2.E calls on APEC Economies to: “build capacity to address financial crimes, which threatens everyone’s economic and social well-being. Illicit financial activities such as tax evasion, corruption, terrorist financing, computer fraud, money laundering and other financial crimes are a global problem requiring coordinated responses within governments and between APEC Economies.” The Cebu Action Plan also called for the OECD to prepare, within two to four years, “a report exploring ways to strengthen capacity in tackling tax crimes and other related crimes in APEC Economies.” This report responds to that mandate by bringing together the legal instruments, policy tools, and capacity building initiatives available to enhance the fight against tax crimes, drawing on examples and successful practices in APEC Economies.