Aims: Active commuting to school (ACS), a source of physical activity (PA), has declined in many countries over recent decades. This study investigates ACS and the factors associated with it among Finnish children and adolescents across two generations: those born between 1965–74 and 1998–2010. We also explore potential generational differences in these associations. Methods: School commuting was self-reported by 2075 participants of the ongoing population-based Young Finns Study in 1983 (generation 1 (G1), aged 9–18, 52% female), and by their 1137 offspring in 2018 (generation 2 (G2), aged 8–20, 53% female). Factors associated with ACS and the moderating effect of generation on these associations were examined using generalized estimating equation models for clustered binary data, for summer and winter seasons separately. Results: A greater distance to school ( p < 0.001) and belonging to G2 ( p ⩽ 0.049) were negatively associated with ACS during both seasons. High parental leisure-time PA ( p ⩽ 0.025 for both seasons) and urban living area ( p < 0.001 for summer) were positively associated with ACS. Generation moderated the associations of school grade and parental income with ACS in the summer ( p ⩽ 0.015). Among G1 only, attending lower secondary school (vs. primary school) was negatively associated with ACS, while higher parental income was positively associated with ACS. Neither gender nor parental education was associated with ACS. Conclusions: ACS was less common among the younger generation. Several correlates of ACS were identified, with generational differences. These findings can inform further research and guide policy decisions to promote ACS and ultimately enhance the PA of children and adolescents.