Background <p>Smartphone addiction is increasingly prevalent, particularly among younger individuals, and has been linked to poor sleep quality. This study aims to assess the effects of smartphone addiction, usage time, socio-demographic factors, relationship with parents, parents’ smartphone usage duration, and earthquake-related experiences on sleep quality among adolescents in the earthquake-affected Kahta district of Adıyaman, Turkey.</p> Materials and methods <p>A cross-sectional study was conducted between June 1st and July 31st 2024 with 394 adolescents aged 12 to 18. Data were collected using a questionnaire that included socio-demographic variables, the Pittsburgh Sleep Quality Index (PSQI), and the Smartphone Addiction Scale.</p> Results <p>The prevalence of smartphone addiction was 57.9%, while 66.2% of participants had poor sleep quality. Adolescents using smartphones for more than two hours daily had a higher frequency of poor sleep quality (<i>p</i> = 0.024). Parental influence was significant: participants whose mothers used smartphones for more than one hour daily had a 2.03 times higher risk of poor sleep quality (<i>p</i> = 0.022). Adolescents with poor relationships with parents had a significantly higher risk of sleep disturbances (<i>p</i> &lt; 0.001). Additionally, those who experienced intense fear during the earthquake or lost loved ones showed significantly worse sleep quality (<i>p</i> = 0.007).</p> Conclusion <p>Smartphone addiction and prolonged usage are strongly associated with poor sleep quality among adolescents. Maternal smartphone use, affects adolescent sleep. Moreover, traumatic experiences related to the earthquake, such as fear and loss, significantly worsen sleep quality. These findings highlight the need for interventions addressing both smartphone addiction and family dynamics to improve sleep health in disaster-affected adolescents.</p> Clinical trial number <p>Not applicable.</p>