Introduction: Childhood adversity is a major risk factor for psychiatric disorders and has especially been associated with an admixture of depressive, anxiety, and psychosis symptoms. Identity formation, a main developmental task during adolescence, may be impacted by these adverse experiences and act as an important process in the association between childhood adversity and psychopathology. Methods: We investigated the association between childhood adversity, identity formation, and depressive, anxiety, and psychosis symptoms cross-sectionally in 1913 Flemish adolescents between 11 and 20 years old (mean = 13.76, SD = 1.86). Adolescents completed questionnaires during the first wave of the SIGMA study between January 2018 and May 2019. Results: Childhood interpersonal adversity was associated with increased identity confusion and decreased identity synthesis. Additionally, identity confusion was associated with increased self-reported levels of psychopathology and potentially mediated the association between childhood adversity and psychopathology. Conclusion: This study highlights the importance of promoting healthy identity formation in adolescents with and without exposure to adverse childhood experiences.