Corruption is typically depicted as a result of one of two factors: a lack of political accountability or insufficient state capacity. Nonetheless, substantial variation in corruption levels exists even within the set of politically unaccountable high-capacity regimes. In this paper, we examine a third determinant of corruption ‐ the ideological appeal of the government ‐ and demonstrate that this variable can explain variation in the types and levels of corruption experienced in politically unaccountable regimes. Using a model of both moral hazard and adverse selection, we predict that (1) regimes that inspire the intense ideological loyalty of the populace are likely to enjoy low levels of petty corruption and that (2) autocratic regimes that enjoy such intense support from only a narrow segment of the populace will erect credible anti-corruption institutions. Political corruption, by contrast, need not covary with levels of ideological support. We illustrate the mechanisms of our model through a series of case studies that demonstrate the importance of ideology in driving levels of corruption ‐ with a particular focus on low levels of corruption in ‘developmentalist’ regimes. Finally, we discuss the relevance of our findings to other ‐ democratic ‐ political settings.