It is often assumed that parental union dissolution leads to more egalitarian gender ideologies among children. Yet evidence on variations in gender ideologies by family structures is scant and based mostly on cross-sectional data. This study offers a closer examination of whether any effect of parental union dissolution can be explained by parents restructuring work and care responsibilities along more egalitarian lines after separation. Drawing on longitudinal data from the UK Millennium Cohort Study, this study applies fixed-effects panel models to estimate the effects of parental union dissolution on gender ideologies of 6,577 adolescents between ages 11 and 14. Parental separation is found to result in more egalitarian gender ideologies toward female employment among boys but not among girls. In line with the role restructuring argument, the positive effect of separation on egalitarianism is driven by boys, whose fathers had rarely had full responsibility for childcare before separation. By highlighting differential effects and possible mechanisms, the findings offer a more nuanced understanding of the implications of increasing deinstitutionalization of family relationships.