<p>Internalizing and externalizing problems have been documented to frequently co-occur, yet their joint developmental trajectories and the influences of contextual and individual factors remain poorly understood, particularly among adolescents in resource-limited regions of China. This three-wave longitudinal study investigated independent and joint developmental patterns of anxious/depressive symptoms and aggressive behavior, with attention to the predictive roles of contextual factors (childhood emotional abuse and neglect), individual personality characteristics (rejection sensitivity), and cognitive factors (coping styles and meaning in life). Surveys were administrated to 1542 high school students (45.1% boys) at three time points with six-month intervals. Parallel process latent growth mixture models identified four distinct joint trajectories of anxious/depressive symptoms and aggressive behavior: dual-high-growth group, dual-moderate-growth group, healthy group, and dual-high-decline group. Childhood emotional abuse, emotional neglect, rejection sensitivity, and negative coping were significant risk factors for comorbid symptom trajectories, while positive coping and meaning in life emerged as protective factors. These findings have important implications for understanding the complexity of comorbid internalizing and externalizing behaviors during the high school years in underdeveloped regions of China.</p>