An emerging body of work on population health focuses on issues of women’s status with the empowerment of women emerging as a centerpiece of contemporary development goals and public policy. One particularly significant aspect of empowerment is female political representation with large increases in the number of female legislators seen in recent decades. Recognition of this has spawned work on the sociodemographic consequences of such increases, including important work on the joint relationship between female political empowerment, economic development, and population health. Yet, missing from contemporary research is consideration of economic inequality. This seems particularly problematic given the unique role of inequality in economic development, large increases in inequality in the 21^st century, and extensive evidence of robust inequality effects on population health. Against this backdrop, this paper has two objectives. First, we offer a micro-macro theory that links female political representation, income inequality, and population health. We do so by specifying micro-, meso-, and macro-foundations that explain why female political representation would matter for population health, how it connects to income inequality, and how political-economic conditions shape its efficacy. Second, we test this theory with fixed-effects regression approaches and panel data comprising 138 countries spanning 1990 to 2014. Results indicate that a) there is clear evidence of critical mass effects where female political representation are large, negative effects on mortality when the percentage of women in parliament exceeds 25%; b) these effects are only seen in contexts characterized by low extents of democracy; c) these negative effects become increasingly larger when income inequality is higher; and d) the resulting estimates imply very large effects that robust across four measures of mortality. Implications for theory, research, and public policy on population health and social development are discussed.