Fairness is central to morality. Previous research has shown that children begin to understand fairness between the ages of four and six, depending on the context and method used. Within distributive contexts, there is little clear evidence that children have a concept of fairness before the age of five. This research, however, has mostly examined children's explicit verbal responses to questions about unequal distributions—a method that often underestimates children's knowledge. In the current study, we instead examined emotional and behavioral signs that children notice and dislike inequality. We distributed an unequal number of rewards (stickers) among pairs of children (the ages of three to five years) and probed their responses to the inequality. Both implicit and explicit measures revealed that children as young as three years old notice and react negatively to an unfair distribution, particularly when they receive less than their partner. The few age trends that were found involved verbal (explicit) responses, providing evidence that although children do not explicitly talk about fairness until the age of five or six, this talk is an effort to explain emotional reactions that emerged earlier in development.