This study explored cross-sectional gender and grade level trends in emotional literacy and interpersonal competence among 913 elementary and middle school students in Japan. Students were presented with two hypothetical scenarios involving mixed emotions and potential interpersonal dilemmas. Results indicated that older children possess greater emotional literacy when compared to younger children. Additionally, girls identified a greater number of emotions, were better able to identify mixed emotions, and were more likely to identify empathic interpersonal behaviours. These gender and grade level considerations may be incorporated into social-emotional learning curricula to enhance the utility and effectiveness of programs for diverse populations.