An emerging body of literature has documented the negative implications high economic inequality can have on children's social and cognitive development. However, little experimental research has directly addressed how wealth discrepancies impact the way children treat others. The current study thus aimed to address the implications of economic inequality on prosocial decision‐making in children prior to commencing formal schooling. Using a novel experimental paradigm, we immersed 4‐year‐old children (N = 58) in a series of games where they played against puppets for rewards. During this process, children were exposed to resource allocations featuring either high inequality or low inequality. We subsequently measured children's donation behaviour, resource division behaviour, and fairness perceptions. As predicted, children were less altruistic when exposed to high inequality compared to low inequality. Contrary to predictions, there was no difference in resource division behaviour or fairness perceptions. This study documents for the first time that exposure to environmental inequality, even if brief and in a controlled experimental setting, can influence young children's prosocial decision‐making.