A growing body of literature studies the personalization of power in authoritarian regimes. Yet, how institutions can become a credible constraint to dictatorial rule is less widely studied. I theorize that corruption is a key factor associated with stronger legislatures in authoritarian regimes. By engaging in corruption, authoritarian elites in ruling coalitions can build up networks of support and influence and ultimately, use their elevated position to impel more legislative powers vis-à-vis the executive. Examining panel data on the strength of legislatures in authoritarian regimes between 1946 and 2010, I show empirically that authoritarian parliaments are stronger when levels of corruption in a given regime are high. The link between corruption and legislative strength is especially strong in the Middle East and Africa, and primarily applies to party-based and military dictatorships. More competitive electoral and legislative processes, however, do not uniformly affect parliaments’ strength. These findings contribute to our understanding of institutional changes in autocracies and highlight the centrality of elite contestations in determining institutional trajectories.