Background <p>Internet addiction (IA) has been reported to be related to attentional bias for addiction-related information and emotional information. Although IA is likely to involve poor sleep quality, no previous studies have examined the interaction between poor sleep quality and attentional bias, and its relevance to IA. The present study aimed to examine the relationship between IA and attentional bias for Internet-related information and emotional information, and tested the moderating role of poor sleep quality in the relationship between IA and attentional bias.</p> Method <p>A total of 71 university students participated in the study (48 females and 23 males; mean age: 20.1&#xa0;years, standard deviation: 4.2&#xa0;years). The participants underwent the visual dot-probe task for measuring attentional bias for Internet-related, negative, and positive information, and completed self-reported questionnaires regarding IA and poor sleep quality.</p> Results <p>The results revealed that attentional bias for negative information and the interaction between poor sleep quality and attentional bias for Internet-related information were significantly associated with IA. Simple slope analysis revealed that attentional bias for Internet-related information was associated with IA among individuals with poorer sleep quality.</p> Conclusion <p>The study revealed that attentional bias for Internet-related information was associated with IA in cases of poor sleep quality. Attentional bias for negative, but not positive, information was associated with IA, and sleep quality did not moderate the relationship between IA and attentional bias for negative information.</p>