BackgroundProblematic Internet use (PIU) remains a significant social concern in Japan and across the globe. Numerous studies have been conducted to examine the prevalence of PIU, and its association with lifestyle habits and mental health status. To the best of our knowledge, few studies have examined the association between parental attachment and PIU in Japan. Furthermore, preventive measures in Japan have primarily targeted adolescents via education. Therefore, in this study we explored the association between PIU and attachment styles among adolescents to seek a new approach for the development of appropriate, effective measures.MethodsA self‐administered survey was conducted at one private (in 2018) and two public junior high schools (in 2020) in Kagawa Prefecture, western Japan. We used the Internet Addiction Test (IAT), the Experiences in Close Relationships–Relationship Structures (ECR–RS) questionnaire, and the Birleson Depression Self‐Rating Scale for Children (DSRS‐C). Multiple regression analysis was performed to examine the association between IAT scores and attachment styles.ResultsOf 1,413 participants (grades 7–9; 700 boys and 713 girls), 39% of the students showed possible PIU and 3% showed PIU. Students with PIU tended to sleep for shorter durations, access the Internet for long hours, and have a poor mental health status (p < 0.01). PIU was significantly associated with insecure attachment (p < 0.0001).ConclusionsThe findings of our study imply that improving attachment styles and developing secure attachment between the child and parent might help mitigate and/or prevent PIU.