BACKGROUND: Across Europe, tobacco use is more prevalent among secondary school students attending vocational tracks compared with students attending academic tracks. The purpose of the present study is to describe trends in social inequality in daily smoking among adolescents between 2002 and 2010 by addressing both absolute social inequality (prevalence difference between vocational and academic tracks) and relative social inequality (prevalence ratio) in seven European countries. METHODS: Analyses were based on data from 15-year-olds who participated in the Health Behaviour in School-aged Children study in 2002, 2006 and 2010 in Belgium, Croatia, France, Germany, Hungary, Italy and The Netherlands (total N = 32 867). RESULTS: Overall, daily smoking decreased between 2002 and 2010 in Belgium, France, Germany and The Netherlands, increased in Croatia and remained stable in Hungary and Italy. Considerable differences in daily smoking according to educational track existed in all countries. Absolute educational inequalities increased dramatically in Croatia and Italy, while relative inequalities showed a tendency to increase in all countries (significant in Belgium and The Netherlands). CONCLUSIONS: Conclusions on social inequality in adolescent smoking may appear differently when described by absolute and relative measures. Especially the large increase in absolute educational inequalities in daily smoking in Croatia and Italy are worrisome and warrant attention from the public health domain. The findings underline the need for appropriate smoking policies and interventions in vocational schools across Europe.