Expectations that others will reciprocate to the benefits they received from us play a crucial role for the establishment of stable reciprocal exchange within social relationships. In the current study, 3- to 5-year-old preschool children allocated in a first phase more resources to one recipient than to another recipient. Subsequently, they had the possibility to ask one of them for valuable resources. The results of Experiment 1 show that preschool children expect others to reciprocate and strategically ask the ones they benefitted more to share with them. Experiment 2 demonstrates that there was no selective resource request when the recipients were absent during children's resource allocations. Experiment 3 showed that children focused on the absolute amount of resources given to the recipients, but did not monitor their own relative generosity in judging to whom of the recipients they had been nicer. This study provides first evidence that preschool children possess reciprocity expectations and point thus to the strategic nature of early social behavior.