Over the past six decades, Latin America and the Caribbean have undergone profound demographic, family, and social transformations that have reshaped household structures across the region. These changes include rapid fertility decline, increases in life expectancy, the spread of cohabitation and union dissolution, and a substantial rise in births outside stable unions and in single motherhood, among others. All of this has unfolded in contexts marked by high levels of social stratification and economic inequality, which strongly condition individuals’ opportunities and constraints. Household structures are thus continuously formed, dissolved, and reconstituted as families adapt to changing demographic and social conditions, with extended households remaining a persistent feature of family organization despite this evolving landscape.

This dissertation examines changes in household structures in Latin America and the Caribbean over recent decades, with particular attention to extended households, defined as those in which relationships among co-resident members go beyond the conventionally defined nuclear family. The thesis consists of four core essays, preceded by an introductory chapter and followed by a concluding chapter. The first essay (Chapter 2) documents changes in household size and composition in the context of fertility decline. The second (Chapter 3) analyzes how transitions to first union, first birth, and single motherhood are associated with the formation of extended households among cohorts of young adults in Mexico. The third essay (Chapter 4) focuses on household structures among single mothers in Latin America, while the fourth (Chapter 5) examines how different family structures are linked to children’s schooling and women’s labor market participation.

Taken together, the essays highlight both the persistence and the social importance of extended household structures across the life course in the Latin American and Caribbean context. They show how such arrangements often emerge in response to critical life-course events—such as family formation or union dissolution—providing an important safety net in settings characterized by early unions and first births, as well as widespread informality and inequality. The dissertation concludes by outlining open questions for future research on family and household change in the region.