Extant research suggests that supportive work–family policies promote gender equality in the workplace and in the household. Yet, evidence indicates that these policies generally have stronger effects on women’s preferences and behaviors than men’s. In this article, we draw on survey-experimental data to examine how young, unmarried men’s gender ideologies and perceptions of normative masculinity may moderate the effect of supportive work–family policy interventions on their preferences for structuring their future work and family life. Specifically, we examine whether men’s prescriptive beliefs about what work–family arrangements most people ought to prefer and whether men’s descriptive beliefs about what work–family arrangements most of their male peers actually do prefer influence their responses to supportive policies. Our analysis shows that men’s responses to supportive work–family policy interventions are highly dependent upon their beliefs about what their male peers actually want, rather than on their beliefs about what others should want. Specifically, men who believe that their male peers ideally want gender-egalitarian or counternormative relationships are themselves more likely to prefer a progressive relationship structure when supportive work–family policies are in place. These findings provide novel support for sociological theories of masculinity and hold important implications for designing policies that promote gender equality in the workplace and at home.