BACKGROUND: Internet addiction (IA) and depression are common mental health concerns, with burgeoning empirical evidence highlighting their significant comorbid relationship among adolescents. We aimed to establish network structures for IA and depression among Chinese adolescents, and to identify the core and bridge symptoms. METHODS: A total of 8176 participants were recruited from Henan Province, Central China. The 10-item Center for Epidemiological Studies Depression Scale (CESD) and 20-item Self-report Internet Addiction Test (IAT) was used to measure depression and IA, respectively. IA, depression and the co-occurrence network structures were constructed using network analysis. Strength, the centrality index, was used to identify the core symptoms. Bridge symptoms were assessed using the bridge strength. RESULTS: Node CESD7 ("Could not get things going") was the most influential node in the depression network model, followed by CESD1 ("Felt sadness") and CESD2 ("Everything was an effort"). Node IAT16 ("Reluctant to be offline") was the most influential node in the IA network model, followed by IAT20 ("Web made you feel better"), IAT15 ("Fantasized about being on the web") and IAT2 ("Neglected household chores"). CESD7 ("Could not get things going") in the depression-IA network was the most key bridge symptom linking depression and IA, followed by CESD8 ("Trouble focus"). Significant gender difference in edge weights was observed (p = 0.002). LIMITATIONS: This cross-sectional study collected data through self-report measures. CONCLUSIONS: The core symptoms and key bridge symptoms in the networks are crucial for the precise intervention of adolescent depression and IA.