Young children are remarkably compliant with social norms, especially those governing fairness and equality. Yet children also frequently observe and face opportunities to violate those social norms, particularly in situations in which doing so is self-beneficial. In 3 studies, we investigated the conditions under which children adhere to social norms using a novel resource distribution paradigm in which children met an experimenter who expressed either a norm-consistent (equal distribution) or norm-inconsistent (unequal distribution) intention. In Experiment 1, we found that preschoolers generally complied with an experimenter's intention, regardless of its norm consistency. In Experiment 2, the experimenter again expressed a norm-consistent or norm-inconsistent intention but accidentally placed resources in the opposite distribution of that intended. Preschoolers mostly defaulted to the social norm of fairness. However, they were less likely to do so (and more likely to comply with the norm-violating experimenter) when the inequality was self-benefitting. The likelihood of norm defiance in the face of self-benefit appeared to relate to children's affective perspective taking. In Experiment 3, we found that training preschoolers in affective perspective taking increased the likelihood children would defy a norm-violating experimenter's unfair intention. Thus, although preschoolers were generally compliant, both fairness norms and affective perspective taking served as important mechanisms to help children selectively defy adults' instructions and intentions.