The COVID-19 pandemic is believed to have strongly impacted adolescents’ mental health through limiting their day-to-day social lives. However, little is known about the role of (social) risk/protective factors and adolescent mental health. Subclinical psychopathology, and risk and protective factors of n = 173 adolescents (T1 mean age = 16.0; 89% girls) were assessed prepandemic and early-pandemic (T1: 2018/2019; T2: May 2020). Daily-life social interactions were assessed in 6-day experience sampling periods. Correcting for age, multilevel analyses revealed declines in general psychopathology and anxiety symptoms; fewer face-to-face social interactions, more online social interactions; and higher-quality face-to-face interactions during the pandemic than before. Negative associations between psychopathology and the quality of face-to-face peer and family interactions were stronger during the pandemic than prepandemic. The results reflect that, early in the pandemic, the mental health impact on adolescents may have been limited. High-quality face-to-face interactions with family and peers seemed particularly powerful in keeping adolescents resilient.