Estimates project that one in three US adults may have diabetes in 2050. Until very recently, type 2 diabetes mellitus (T2DM) was a disease diagnosed in adults, but as the childhood obesity epidemic has spread, the diagnosis of T2DM in adolescents has become more common. Early indicators suggest that the disease may be more severe and more difficult to manage when diagnosed in adolescents. It is projected that adolescents with T2DM will lose approximately 15 years of life. The economic burden of T2DM rises significantly as the years with disease increase. This grim forecast highlights that not only will the disease burden be significant but the economic burden will be high. The risk for developing T2DM begins in utero. Individual health development trajectories build from this starting point, the result of multiple factors that accumulate across time and are the result of biological conditioning during sensitive developmental periods. A major aim of this chapter is to demonstrate that a life course health development approach to pediatric T2DM is critical to a sound national strategy to prevent and treat pediatric T2DM. We review major factors known to influence the development of pediatric T2DM and track these across childhood. While these factors will likely change over the next decade, what will not change is the importance of placing these factors into context and recognizing that T2DM development is highly sensitive to the timing and social structures of multiple environmental exposures. Research recommendations are discussed through a life course lens.