Exposure to social and ecological adversity during sensitive windows of development often leadto disadvantageous outcomes in adulthood such as reduced social connectedness and shorter lifespan. Consequences of early life adversity can persist across generations. The mother is a crucial component of the early life environment for mammals and plays an important role in shaping offspring development. The mechanisms underlying the associations between early life adversity, adult outcomes, and transgenerational effects are not well established, and the complexities of how early life environments shape the ways offspring prioritize different dimensions of development are only beginning to be understood. This dissertation leverages longitudinal data, detailed behavioral observations, fecal hormone sampling, and noninvasive estimates of infant body size to assess how early life experiences shape development and adult outcomes in a wild population of olive baboons (Papio anubis) in Laikipia, Kenya. Four dissertation papers address: 1) the relationship between a mother’s early life adversity and her maternal effort, physiology, and offspring survival; 2) how the maternal environment shapes the ways developing offspring allocate resources among play, behavioral independence, and growth; 3) the role of interaction style in mediating the relationship between early life adversity and adult female sociability; and 4) the relative importance of female competition over food, mates, and male caretakers. Results of these papers show early life adversity can have lasting consequences on maternal effort and physiology, which in turn shape offspring developmental trajectories. Females who experienced early life adversity were less likely to develop an interaction style that was associated with sociability. Finally, the energetic costs of lactation were the primary driver of female competition, and in light of findings in chacma and yellow baboons, this indicates evolution has finely tuned female baboons’ responses to the social and ecological pressures of their local environments. To better understand the complexities of early life experiences and developmental trajectories, it is important to leverage longitudinal data and create comprehensive models of the maternal environment and infant development.