Caused by persisting traditional gender norms, working mothers with young children are at particular risk of experiencing ambivalent sexism at work, i.e., discrimination based on both negative (hostile sexism) and positive (benevolent sexism) attitudes towards women. In this study, we integrate ambivalent sexism and conservation of resources theories to disentangle the negative effects of ambivalent sexism investigating how hostile and benevolent sexism are related differently to work-family and family-work conflicts and link both types of sexism through these conflicts to impaired physical health. Using data from three-wave surveys of 719 working mothers with young children, we find support for our theoretical model pointing to unambiguous detrimental effects of hostile sexism on work-family and family-work conflicts and eventually health which are more severe for mothers with a more egalitarian gender role orientation. Supporting the proposed differential effects of benevolent sexism, the findings corroborate that benevolent sexism increases family-work conflict but reduces work-family conflict and produces interesting opposing mediation effects. Individual gender role orientation only governs the effect on family-work conflict. Based on our theorizing our results uncover important new insights into the paradoxical mechanisms of how ambivalent sexism reproduces gender inequalities and deteriorates victim’s health.