The transition to parenthood exacerbates gender inequality in couples’ division of paid work. While this is widely documented for general populations, in particular, potential underlying mechanisms of this phenomenon remain un(der)explored for couples with different migration backgrounds. Hence, this paper examines how women’s pre-birth relative wage potential affects the gender division of paid work after the transition to parenthood in Belgium among native, Southern-European and non-European origin couples. Our results show that, among all couples, the division of paid work is more gender-equal after childbirth when women’s wage potential is higher than or similar to that of their male partner. However, there is substantial variation by couples’ migration background and relative wage potential in partners’ gender division of paid work and the extent to which it changes after parenthood. These findings suggest that both normative and institutional factors moderate the impact of partners’ relative resources on couples’ division of paid work after parenthood, particularly among non-European origin couples.