Given that shyness has been consistently linked to Internet addiction in youth, an examination into the mediating effect of a desire to avoid loneliness on the shyness-Internet addiction link could offer potential insights into a possible explanatory mechanism as well as directions for Internet addiction prevention and intervention in young adulthood. Thus, the aim of this study is to investigate the mediating role of loneliness avoidance in the relationship between shyness and Internet addiction among 286 youth Internet users. Shyness was significantly and positively correlated with loneliness avoidance and Internet addiction. In addition, loneliness avoidance was significantly and positively correlated with Internet addiction. Most importantly, loneliness avoidance may predispose shy youth to become addicted to the Internet. Theoretical and practical implications of the research findings for youth wellness are addressed in this study.