In this paper we analyze the relationship between fertility decline, and changes in women’s lives, gender equality and gender relations in the Indian state of Tamil Nadu over the last 40-50 years. Using secondary quantitative analysis, published and unpublished quantitative and qualitative research, and interviews with experts, we examine how fertility decline in Tamil Nadu manifested in changes in the social and economic value of children, the shift from a focus on having a large quantity of children to investing more in fewer children, and the shrinkage of women’s lifespan devoted to childbearing. In turn, we explore how these changes have influenced specific domains of women’s lives, gender equality and gender relations. We also describe how Tamil Nadu’s history of progressive social activism, combined with economic poverty until recently, has influenced these dynamics. We find that, following fertility decline, women’s lives have improved in the realms of higher education, marriage spousal choice, and – to some extent – employment opportunities. Gender inequality also has decreased in education and employment. However, these changes have yet to lead to notable shifts in societal gender relations and norms, as manifested in marriage practices, dowry, and intimate partner violence.