Aims: The aim of this study was to find out whether family members’ (mother, father, siblings) and best friend’s smoking is related to 9th grade pupils’ daily smoking in Eastern Finland and in the Pitkäranta district, in the Republic of Karelia, Russia, and whether these relations have changed in these two culturally very different neighbourhood countries from 1995 to 2013. Methods: Data comprised four cross-sectional studies in all schools of the Pitkäranta region and selected schools in Eastern Finland. In data analyses, structural equation modelling techniques were used. Results: Our findings showed that best friend’s smoking had the strongest influence on adolescents’ smoking in both countries and study years (p < .01). The relations among family members were highly different between Pitkäranta and Eastern Finland, particularly in 2013. Conclusions: Results suggest that health promotion in schools should take into account cultural impacts and pay special attention to pupils who have family members and friends who smoke.