This paper provides a broad empirical overview of the relationship between family change and socio-economic development drawing on 30+ years of Demographic and Health Survey data from 3.5 million respondents across 84 low- and middle-income countries (LMICs). We conduct two sets of analyses. First, we document global and regional-level associations between the Human Development Index (HDI) and novel indicators reflecting multidimensional family change. Second, we use methods from the growth convergence literature to examine whether – and in which domains – there is evidence of cross-country convergence in family indicators over levels of development. We show that families in LMICs have transformed in multiple ways, changing differently across domains, world regions, and genders. Fertility, intra-couple decision-making, and women’s life-course timing indicators are strongly associated with HDI, yet cross-country convergence is limited to the latter domain. Marriage, cohabitation, household structure, and men’s life-course timing indicators are more weakly associated with HDI, and span a broad spectrum of convergence dynamics ranging from divergence to modest convergence. We describe this scenario as “persistent diversity with development,” and shed light on the underlying regional heterogeneity – driven primarily by sub-Saharan Africa.