Interpersonal emotion regulation entails a wide array of strategies aimed at influencing others’ emotions. Despite its importance for successful social interactions, only a few studies have evaluated interpersonal emotion regulation in children. In detail, the study of developmental changes in the use of emotion regulation strategies overlooked age, gender and cultural differences across different emotions. To address this gap, the present study used the serious game Emodiscovery, a simulation game targeted at 8–10-year-olds, which measures the strategies selected by children to improve the emotions of anger, sadness, and fear displayed by 3D virtual characters. One-hundred British (M = 9.10 years; 39% girls) and 108 Spanish (M = 9.04, 44% girls) 8–10-year-olds played 3 different levels or scenarios of the game. In each level, the character displayed a negative emotion (i.e., sadness, anger, and fear, respectively) and children were first asked to indicate what emotion the character was feeling and afterward to interact three times with the character to improve his or her mood. In each interaction, 4 possible regulation strategies (2 adaptive and 2 maladaptive) were displayed for children to select. Results showed that in the scenario where the character was displaying sadness, 8-year-olds chose significantly less adaptive strategies than 10-years-olds. In the scenario where the character was angry, boys who accurately recognized the emotion of anger chose more adaptive strategies than those who did not recognize the emotion. For the scenario depicting fear, boys chose less adaptive strategies than girls. The obtained results highlight the importance of looking at specific emotions when researching interpersonal emotion regulation. (PsycInfo Database Record (c) 2021 APA, all rights reserved)