Identifying the key determinants of poor developmental outcomes is critical in improving the lives of millions of children who suffer from poor physical growth and cognitive deficits. Much research suggests that early life conditions, particularly those experienced within the household, critically influence children’s development across the life course. In this dissertation exercise, I explore how three dimensions of early experiences – prenatal conditions, parental education, and household socioeconomic conditions – influence children’s physical and cognitive development. Chapter 1 finds that the influences of low birth weight, often touted as a key determinant of later health, wane over time with increasing importance of postnatal factors. Chapter 2 also counters accepted evidence that maternal education matters more for children’s physical development by finding that both parents’ education matters equally in both infancy and childhood with no mechanisms distinguishing maternal and paternal education. Chapter 3 supports the evidence that household socioeconomic status matters for children’s cognitive development and finds that household assets are the critical determinant of cognitive status. Findings from each of these chapters will not only contribute new scientific evidence but will also help inform policies and programs to improve children’s health and well-being