In Europe we are witnessing a progression from the ‘traditional’ gender gap, where men are more left-wing than women in ideology and vote choice, to the ‘modern’ gender gap, where women are more left-wing than men (Emmenegger & Manow, 2014; Giger, 2009; Inglehart & Norris, 2003). The traditional gender gap has been attributed to gender differences in religiosity, labour force participation and longevity, although these variables have had less success in accounting for the modern gender gap (Giger, 2009). Despite interest in the emergence of the modern gender gap, little attention has been given to Inglehart and Norris’ contention that it can be attributed to generational replacement: younger cohorts are more left-wing than older cohorts, but this change has been greater for women than for men. This suggests the modern gender gap is slowly emerging as younger and more left-wing cohorts of women replace their older, more right-wing counterparts. This is expected to produce a complex pattern of gender gaps in Europe, with those in older birth cohorts displaying the traditional gender gap and those in younger birth cohorts displaying the modern gender gap. Using the Eurobarometer and the European Values Survey to get a suitably long time series, this paper interrogates the generational explanation for the supplanting of the traditional gender gap with the modern gender gap in many European countries. It also explores possible explanations for gendered cohort change including declines in religiosity and increases in female labour force participation and postmaterialism across generations.