Background: Associations between internet gaming disorder (IGD), psychological distress, and sleep have been reported. However, little is known whether such associations exist across siblings; that is, whether adolescents’ IGD symptomatology may impact their siblings’ psychological distress and sleep. This study aimed to examine whether siblings' IGD symptoms may relate to depressive, anxiety symptoms or sleep quality among each other.

Methods: Using a cross-sectional design with two-stage cluster sampling, 320 dyads of adolescent students and their siblings participated in the study. Each dyad completed the Internet Gaming Disorder Scale-Short Form (IGDS-SF9), the Depression Anxiety Stress Scale-21 (DASS-21), and the Insomnia Severity Index (ISI). The actor–partner interdependence model (APIM) was applied to examine relationships between IGD, psychological well-being, and insomnia severity in the dyadic data.

Results: Actor effects of IGDS-SF9 scores on depression, anxiety, stress, and insomnia severity were significant in both adolescents (e.g., adolescents’ IGDS-SF9 scores on their depression scores) and their siblings (e.g., IGDS-SF9 scores of adolescents’ siblings’ scores on their depression scores). Partner effects of IGDS-SF9 scores on depression, anxiety, stress, and insomnia severity were significant in both adolescents (e.g., adolescents’ IGDS-SF9 scores on their siblings’ depression scores) and their siblings (e.g., IGDS-SF9 scores of adolescents’ siblings on adolescents’ depression scores).

Conclusions: The present study demonstrated that adolescent students and their siblings had mutual impacts of IGD on psychological health and sleep. Thus, healthcare providers may consider involving siblings when they design programs reducing IGD-related problems or improving psychological health and sleep for adolescents.