Using data collected from the EU Kids Online II project, a random stratified sample of 18.709 adolescents aged 11-16 years, from 25 European countries, was used to analyse the relationship between excessive Internet use (EIU) and a set of psychological, behavioural, and demographic variables. At a European level, psychological variables were the best predictors, accounting for more of the variation in EIU than both behavioural and demographic variables combined. On a national level, the most stable predictor was emotional difficulties, while all the other variables shifted across countries.