A systematic diagnosis of a revenue administration is a prerequisite to developing a successful strategy for its reform. However, given the complexity of tax and customs administration, this is not a simple task. A host of external and internal factors need to be analyzed to uncover the roots of organizational and institutional dysfunction. Also, the diagnosis needs to be done in a participatory manner to build consensus around the causes for inadequate performance and their remedies. This framework enables a step-by-step analysis of the environment, history, resources, strategy, transformation processes, outputs and feedback mechanisms of the revenue administration system, with a view to identifying systemic deficiencies that lead to inefficiency and ineffectiveness in its operations. Besides a detailed set of diagnostic questions for each area of analysis, the framework provides illustrations of frequently encountered problems and their possible remedies. The framework can be used in a group setting involving different stakeholders, to guide brainstorming sessions and draft reform strategies