Purpose: First, to describe adolescents' health information sources and knowledge, health literacy (HL), health protective measures, and health-related quality of life (HRQoL) during the initial phase of the Covid-19 pandemic in Norway. Second, to investigate the association between HL and the knowledge and behavior relevant for preventing spread of the virus. Third, to explore variables associated with HRQoL in a pandemic environment. Methods: This cross-sectional study includes survey data from 2,205 Norwegian adolescents 16-19 years of age TRANS. The participants reported on their health information sources, HL, handwashing knowledge and behavior, number of social interactions HP social interactions TRANS, and HRQoL. Associations between study variables and specified outcomes were explored using multiple linear and logistic regression analyses. Results: Television (TV) and family were indicated to be the main sources for pandemic-related health information. Handwashing, physical distancing, and limiting the number of social contacts were the most frequently reported measures. HL and handwashing knowledge and HL and handwashing behavior were significantly associated. For each unit increase on the HL scale, the participants were 5% more likely to socialize less with friends TRANS in comparison to normal. The mean HRQoL was very poor compared to European norms. Being quarantined or isolated and having confirmed or suspected Covid-19 were significantly negatively associated with HRQoL, but seeing less friends TRANS than normal was not associated. HL was significantly positively associated with HRQoL, albeit of minor clinical importance. Conclusion: Adolescents follow the health authorities' guidelines and appear highly literate. However, high fidelity requires great sacrifice because the required measures seem to collide with certain aspects that are important for the adolescents' HRQoL.