OBJECTIVE : We examined changes in sleep-onset difficulties over time and associations with physical activity and screen time behavior among adolescents. METHODS : We used data from last four survey waves of the Health Behavior in School-Aged Children (HBSC) study (2002-2006-2010-2014). Multilevel logistic regression analyses were conducted to explore associations between regular sleeping difficulties, excessive screen time exposure and being insufficiently physically active (i.e., < 60 min daily) among 33 European and non-European countries. RESULTS : Findings indicate an increase in the prevalence of sleep-onset difficulties and in excessive screen time exposure and a small but significant increase in physical activity levels. Additionally, adolescents exceeding 2-h daily screen time had 20% higher odds of reporting sleep-onset difficulties, while no association was found for physical activity. The strength of the association between screen time and sleep-onset difficulties increased over time, which may reflect a change in type of screen time use (e.g., the increased use of easy accessible screens such as smartphones and tablets). CONCLUSIONS : Effective strategies to reduce screen time are key to reverse the detrimental trend in sleep-onset difficulties among adolescents.