Past research on emotional clarity (EC), the ability to identify and label one’s own emotions, has illustrated a connection between EC deficits and poor psychosocial outcomes during the adolescent years. For youth ages 12-17, low EC is associated with internalizing problems, dysfunction in peer and parental relationships, and risky behavior such as substance use. Likewise, high EC is linked with positive outcomes, such as psychosocial maturity and adaptive emotion regulation skills. Although past research has connected EC to psychosocial outcomes during adolescence in cross-sectional and longitudinal designs, no studies have traced the trajectory of EC over time to determine the developmental course of the construct during adolescence. Thus, this study investigated how EC developed over five years during adolescence and what factors were associated with the developmental trajectory of emotional clarity. Results indicated that EC tended to decrease over adolescence, and females, on average, had a steeper decline of EC over time than males. The trajectory of EC change predicted psychosocial outcomes, including depression, family functioning, well-being, and the trajectory of peer victimization over time. Results are discussed with the ultimate goal of informing novel prevention and intervention programs to promote adaptive emotional functioning during an influential time in human development. / Psychology