Gender penalties in pension outcomes are widely acknowledged and have been documented for majority populations in various settings. A recurring finding is that the gendered impact of family formation on work–care trajectories adversely affects women's accumulation of pension rights over the lifecourse relative to men. Although maternal employment is particularly low in migrant populations, few papers have explicitly addressed pension protection of migrant women. Using longitudinal microdata from the Belgian Social Security Registers, we analyse whether entry into parenthood differentially affected the build-up of first pillar pension rights of working-age migrant women compared to natives between 1998 and 2010, further distinguishing by origin group and migrant generation. The results show that native women are most likely to build up pension rights through full-time employment both before and after parenthood. In contrast, first-generation women and women of Turkish and Moroccan origin are more likely to build up pension rights though assimilated periods or rely on derived pension rights after parenthood, even when controlling for type of pension build-up before parenthood. We conclude that policies reinforcing individualisation of pension rights based on employment or decreasing the importance of derived rights may erode pension protection of groups having limited access to the labour market, and require co-ordination with employment and family policies that support the combination of work and care responsibilities.