ABSTRACT: This chapter sets out the experience of Transparency International (TI) in fighting corruption worldwide in the water sector. It focuses on identifying the sources of corruption in the sector and the available toolkits (best practices) for combating it. Case studies from Cambodia, Japan, Colombia and Pakistan are used to illustrate some of the major points. The chapter highlights the importance of forming inclusive multi-stakeholder approaches to fight corruption, involving government, regulators, utilities, the private sector and civil society organizations (CSOs) and uses as an example the Water Integrity Network (WIN)—a recent initiative to set up a network to combat corruption in the water sector.