AbstractOpposition coalitions under electoral authoritarianism have been associated with greater likelihood of opposition victory and democratization. I argue, however, that coalitions also entail significant downside risks with implications for longer term prospects for democracy. Where coalitions produce strong electoral outcomes but fail to force turnovers, regimes are left with both the incentive and capacity to repress and reconsolidate power. I show cross‐nationally that opposition coalitions are associated with stronger opposition performance overall, but that when oppositions fail to take power, exceptionally strong performance is associated with greater autocratization in the subsequent years, including increased repression and poorer electoral quality in future contests. Probing the case of Cambodia, I demonstrate how the very features that make opposition coalitions a useful tool in strengthening performance also invite new threats from regimes. I argue that this makes coalition formation a particularly risky proposition.