We examine cultural and ideological barriers to gender equality in a young democracy, Indonesia, where women’s political representation has increased slowly since democratization, but where survey results point to declining support for women’s political leadership. In both country and comparative literature, the effect of ideological factors—including religion—on voter support for women candidates is contested. Using results of a nationally representative survey, we group respondents according to a “political patriarchy” index. We find that being a Muslim is a strong predictor of holding patriarchal attitudes; university education is associated with gender-egalitarian views. Patriarchal views, in turn, are associated with opposition to increasing Indonesia’s gender quota and with lower levels of self-reported voting for female candidates. Our findings suggest that patriarchal attitudes drive both policy preferences and voter behavior. We conclude that Indonesia’s recent conservative Islamic turn likely underpins widespread—and increasing—opposition to gender equality in politics.