Unequal opportunities are a defining feature of modern economies, yet individuals often disagree about whether and how inequalities deriving from unequal opportunities should be compensated. This paper studies whether experiencing unequal opportunities causally shapes redistributive behavior. We implement a controlled laboratory experiment using a spectator design in which individuals first experience either an advantaged or disadvantaged version of an effort task and then evaluate redistribution between two workers who faced unequal task difficulty. By experimentally separating the experience of advantage or disadvantage from success or failure, we isolate how exposure to unequal opportunities affects beliefs and redistributive decisions. We find that experiencing disadvantage leads spectators to attribute greater importance to circumstances in determining success and increases redistribution toward disadvantaged workers when redistribution is costless to the spectator. While redistribution decreases when it entails a personal cost, the gap between advantaged and disadvantaged spectators persists. These results provide causal evidence that lived experience of disadvantage reshapes beliefs about merit and fairness, with implications for how unequal opportunities are evaluated in redistributive decisions.