A large number of “independent” anticorruption agencies (ACAs) sprung up around the world in past decades. Yet little comparative work has been done to explain the diversity of their organizational forms or development trajectories. Using insights from regulatory theory and the regulation of government literature, this article argues that the formal powers and independence ACAs are granted crucially depend on whether external and/or domestic impetuses for setting them up can counterbalance governments' incentives for no action, or only symbolic action. The ACAs' initial mandate influences but does not determine how they fare in later life: Support or obstruction from ruling governments, their own ability to use strategic resources, and leadership shape the extent to which the agencies are able to carry out their tasks in practice. These arguments are examined through comparison of three ACAs in the European Union's “new” member states—Latvia, Poland, and Slovenia.