Second Demographic Transition (SDT) theory highlights how secularisation and individualism dis-rupted traditional family behaviours, e.g., high fertility and lifelong universal marriage, in Western countries. While non-traditional family behaviours appeared in Nordic countries first, later diffusing to other regions, variations in approval across educational groups and historical time remain underexplored. This study examines approval levels towards non-traditional behaviours—voluntary childlessness, nonmarital cohabitation, nonmarital childbearing, parental divorce with children under 12, and mothers working with children under 3—across sociopolitical regimes in Europe, education levels, and historical time. European Social Survey data (2006, 2018) from 21 countries revealed different approval depending on the family behaviour. Approval was widespread for nonmarital cohabitation, nonmarital childbearing, and mothers working, but voluntary childlessness and parental divorce were less accepted. Country differences were not always as predicted by SDT theory: Nordic countries showed the highest approval for all non-traditional family behaviours, followed by Southern Europe, while Western and Eastern Europe were more resistant. Approval of maternal employment and parental divorce varied by education, with higher approval among the highly educated. Regarding historical changes, in Southern Europe the initially higher approval among the highly educated for unmarried cohabitation and non-marital childbearing in 2006 had levelled out by 2018.