n the field of emotion development, there is a shortage in different approaches to evaluate emotion processes, particularly in adolescents. The current study developed an Implicit Association Test (IAT) for adolescent emotion expression. Participants were 120 adolescents (M[subscript age] = 14.69 years, SD = 11.11 months; 75.8% White; 50% girls) and their parent (96.7% mothers). Convergent, divergent, and predictive validity were examined. Initial validation of the IAT was demonstrated through negative associations with youth's reluctance to express emotions. Parental report of their child's attitudes toward expressing emotions provided additional evidence of convergent validity. Parent-child concordance was found on explicit attitudes toward emotional expressivity. Significant relations between emotion expression attitudes and adolescents' report of their own social experiences established predictive validity. Examining implicit attitudes may provide a way to assess youth attitudes toward emotional expressivity that reduces self-report bias.