The article provides an overview of the involvement of civil society organiza!ons and citizens in public procurement. It analyses the main challenges and opportuni!es arising from civil society procurement monitoring including: the advantages and disadvantages of an explicit monitoring mandate for civil society in procurement legislation; the challenges and opportunities connected with different levels of access to procurement information across countries; the main problems and possible solutions in raising funds to support civil society procurement monitoring; the various monitoring techniques and how CSOs can select what projects to monitor; the problems connected with monitoring projects that require high levels of technical expertise, such as complex infrastructure contracts. The article points out some best practices in civil society procurement monitoring, based on exis!ng experiences, common mistakes and success stories.