Childhood obesity, a growing global health concern, is significantly influenced by maternal nutrition during pregnancy. Emerging research highlights the role of maternal dietary patterns in regulating fetal gene expression and epigenetic modifications, affecting long-term health outcomes. This chapter explores the intricate connections between maternal diet, fetal metabolic programming, and the risk of childhood obesity. It emphasizes the importance of a balanced intake of macronutrients (carbohydrates, proteins, and fats) and micronutrients (iron, folate, calcium, iodine, and vitamins) to ensure optimal fetal growth and development. Additionally, the chapter delves into the impacts of maternal obesity, gestational weight gain, and gestational diabetes mellitus on childhood obesity. It discusses the influence of lifestyle factors, such as physical inactivity, substance use, and environmental exposures during pregnancy, on fetal health. The review concludes with a discussion of predictive biomarkers, including C-reactive protein, adipokines, and metabolomic profiles, for identifying obesity risk in offspring. Interventions targeting maternal nutrition and health behaviors are pivotal for mitigating the childhood obesity epidemic.