The article outlines a programme theory for the Swedish school inspection. The theory has a format of 'if … then … because', whereby the last term states one or more generative mechanisms behind the reactions to inspection, and the former terms imply what the inspectorate does and which reactions it receives. The assumptions of the theory are tested regarding their precision of definition, consistency and empirical status. No research has as yet confirmed a general positive effect of the Swedish inspection on learning and school development. Programme theory, however, suggests that such effects are mostly context-dependent, and thus will vary between schools and school authorities. A complicating feature of the present inspection is its objectivist ethos, which is at odds with the Swedish tradition of a transactional ethos in inspections.