Apprehending the development of complex emotions is crucial to understand the development of decision-making. Regret and relief are complex counterfactual emotions, which can arise in private or in social contexts. The aims of the present study were (i) to uncover the development of regret and relief and (ii) to explore the development of a social form of regret and relief in a context of competition. The first experiment provides evidence that the ability to experience regret and relief continues to develop until adolescence, consistent with the implication of the orbitofrontal cortex in their experience. In a context of competition, we observed that adolescents were less able to experience social regret compared to children and adults, whereas their feeling of social relief was reinforced. Besides, adolescents failed to question the appropriateness of their initial decision. This result could provide an explanation for adolescents’ enhanced propensity to engage in risky behaviours.