We test the separate and joint effects of strategy and regulation on public service performance. Strategy is measured as the extent to which service providers are prospectors, defenders and reactors. Regulation is assessed on the basis of the number of inspection events and service managers' perceptions of the supportiveness of regulators. We find that, controlling for prior performance and the level of service expenditure, prospecting is a more successful strategy than defending or reacting. In addition, inspection events generally disrupt the relationship between strategy and performance, but regulation that is supportive reinforces this relationship. The evidence suggests that the impact of organizational strategies in the public sector is contingent on the characteristics of regulatory regimes.