PURPOSE: Subthreshold depression refers to a condition involving clinically significant depressive symptoms that fall short of meeting the diagnostic criteria for major depressive disorder (MDD). Identifying risk and protective factors associated with the progression of subthreshold depression in early life is essential for timely prevention. However, there is limited research on this topic among early adolescents. METHODS: This study analyzed data from the Adolescent Brain and Cognitive Development study to investigate the factors influencing the progression of subthreshold depression in individuals aged 9-13 years. Among 1,020 participants identified with subthreshold depression using the Child Behavior Checklist, 3 clinical outcomes were examined: developing MDD, persistent subthreshold depression, and remission from subthreshold depression. Using 31 diathesis-stress-related variables covering demographics, mental and physical health, and environmental factors, logistic regression was employed. RESULTS: Compared to baseline healthy controls, adolescents with subthreshold depression had a 5.7-fold odds ratio for converting to MDD. Behavioral inhibition and traumatic experiences were identified as key risk factors in the transition from subthreshold depression to MDD. Individuals with subthreshold depression who exhibited traits of lack of perseverance, recent social deprivation, and school disengagement were likely to remain in subthreshold depression. Those who experienced remission from subthreshold depression had no family psychiatric history and experienced a good school environment. DISCUSSION: Our study highlights the possible associations among maintaining regular sleep, using behavioral activation and resilience-based therapies, and fostering school belonging with enhanced prognosis for adolescents. Further research is needed to explore whether these interventions can reduce the risk of developing MDD.