Adolescence is a developmental period characterized by remarkable volatility and comorbidity in internalizing disorders. Delineating internalizing symptom change in a manner that accounts for symptoms' shared versus distinctive features is imperative to an understanding of their development. An additional question concerns how vulnerabilities for internalizing disorders relate to development of internalizing symptoms. Cross-sectional and prospective associations between neuroticism and internalizing psychopathology are well-established, yet conclusive evidence on neuroticism's relation to the progression of symptom dimensions relevant to internalizing disorders remains absent. In this investigation, we used latent growth curve modeling to characterize the trajectories of tri-level model internalizing dimensions (General Distress, Anhedonia-Apprehension, Fears, Anxious Arousal, Fears of Specific Stimuli, Social Fears, Narrow Depression, Interoceptive/Agoraphobic Fears) and examined whether a general neuroticism factor predicted their growth. We used anxiety and depressive symptom data spanning 6 years, collected from 606 high school juniors mostly vulnerable for internalizing disorders. We observed a pattern of results that varied by symptom dimension. Only Anhedonia-Apprehension showed a distinct increasing trend, on average. Neuroticism predicted an adverse symptom course for the dimension of General Distress. Our results reinforce the notion that neuroticism confers substantial risk for internalizing symptom maintenance and extend past findings by demonstrating that neuroticism forecasts a poor symptom course for General Distress but not narrower dimensions of internalizing. (PsycInfo Database Record (c) 2021 APA, all rights reserved).