Background: The COVID-19 outbreak has profoundly affected the psychological well-being of university students globally. Previous studies have found a positive longitudinal link between fear of COVID-19 (FoC-19) and internet addiction. However, there is a notable gap in the literature regarding COVID-19-specific predictors and underlying mechanisms of internet gaming addiction (IGA). Methods: Integrating the compensatory internet use theory and social role theory as frameworks, a three-wave longitudinal approach was used in this study to test the hypothesized model. Data spanning a duration of one year were gathered from undergraduate students in China. From 2021 to 2022, we conducted online self-report surveys in the midst of the COVID-19 pandemic to obtain participants’ levels of FoC-19, loneliness, depressive symptoms, and IGA. Results: FoC-19 showed a longitudinal positive relationship with IGA. The longitudinal link between FoC-19 and IGA was mediated by loneliness and depression. Gender moderated the direct effect of FoC-19 on IGA, with this effect being significant only among male students and not among their female counterparts. Conclusion: These findings advance our comprehension of the mechanisms and gender differences underlying the link between FoC-19 and IGA, and provide a novel perspective for interventions to reduce IGA.