Background: The COVID-19 pandemic and related policies have amplified the vulnerability of adolescents to the development of posttraumatic stress disorder (PTSD) and dissociation symptoms. This study sought to explore the profile patterns and psychopathological characteristics of co-occurring PTSD and dissociation symptoms in Chinese adolescents. Methods: A total of 57,984 junior and senior high school students in Deyang City, China were recruited between July 13 and July 19, 2020. PTSD and dissociation symptoms, risk factors, and functional impairment variables were assessed using the Global Psychotrauma Screen for Teenagers (GPS-T) instrument. Latent class analysis (LCA) was employed to examine the phenomenology and risk factors of co-occurring PTSD and dissociation symptoms. Analysis of Variance (ANOVA) was utilized to investigate differences in COVID-19 pandemic-related exposure and functional impairment across distinct symptom profiles. Results: A 4-class model was selected as the optimal solution, comprising subgroups of low symptom, predominant PTSD symptom, predominant dissociation symptom, and PTSD-dissociation symptom. Class membership could be significantly predicted by other stressful experiences, social support, childhood maltreatment and psychiatric histories. The PTSD-dissociation symptom class exhibited the most severe COVID-19 pandemicrelated exposure and functional impairment among all classes. Limitations: The cross-sectional design, Chinese cultural background, online survey method and oversimple measurements were the limitations. Conclusions: Our findings extend existing knowledge about the coexisting patterns of PTSD and dissociation symptoms in adolescents, which could assist in identifying high-risk youths. Furthermore, our findings offer recommendations for shaping public health policies and formulating effective clinical interventions for adolescents following the COVID-19 pandemic and lockdown.