With the rapid growth of the novel coronavirus disease 2019 (COVID-19), individuals may try to find related medical information using the internet to overcome their fears. Under such circumstances, individuals with the features of cyberchondria, anxiety sensitivity, and metacognitive beliefs in negative thoughts may suffer more fears than those without these features. Therefore, the present study proposed a model to understand the associations between problematic internet use (PIU), cyberchondria, anxiety sensitivity, metacognition beliefs, and fear of COVID-19. Utilizing a cross-sectional online survey, 651 Iranians completed the following psychometric scales: Metacognition Questionnaire-30 (MCQ-30), Anxiety Sensitivity Questionnaire (ASI), Cyberchondria Severity Scale-Short Form (CSS-12), Fear of COVID-19 Scale (FCV–19S), and Generalized Problematic Internet Use Scale (GPIUS). Structural equation modeling (SEM) was used to assess the proposed model via several fit indices. The indices include Tucker-Lewis index (TLI), comparative fit index (CFI), standardized root mean square residual (SRMR), and root mean square error of approximation (RMSEA). The fit indices (CFI = 0.948, TLI = 0.938, RMSEA = 0.053, and SRMR = 0.001) indicated the good fit between the data and the proposed model. Moreover, fear of COVID-19 was significantly and directly predicted by cyberchondria (β = 0.479, p <.001) and anxiety sensitivity (β = 0.286, p <.001). The relationship between PIU and cyberchondria with fear of COVID-19 was mediated significantly by anxiety sensitivity and metacognitive beliefs. Because fear of COVID-19 was found to be significantly associated with cyberchondria and anxiety sensitivity, healthcare providers may want to provide additional support for those with cyberchondria and anxiety sensitivity tendencies. © 2020 The Author(s) Psychology; COVID-19; Cyberchondria; Internet; Metacognition; Psychological distress.