Research on the impact of participatory institutions in Latin America has not yet examined how they work in authoritarian settings. National autocrats in Mexico implemented participatory reforms during that country’s national electoral authoritarian regime. Building on research on political decentralization in authoritarian regimes, I argue that participatory institutions can be used to channel citizen demands and to incorporate citizens into authoritarian systems, thereby strengthening authoritarian rule. However, following research on democratic participatory governance, I also argue that participatory institutions will work better in this regard when designed from the bottom up rather than from the top down. Statistical analysis of patterns of municipal-level electoral authoritarian support in Mexico shows that bottom-up-designed participatory institutions implemented during electoral authoritarian rule strengthened local political control to a greater extent than top-down-designed political systems. The study supports research revealing the anti-democratic effects of participatory institutions in democratic Latin American nations.