There has been increasing focus on the developmental origins of long-term health and disease, with numerous examples of exposure to diabetes during pregnancy begetting obesity and more diabetes. An open question is whether exposure to lesser degrees of hyperglycemia during pregnancy are associated with adverse metabolic outcomes in children. This question was addressed in the Hyperglycemia and Adverse Pregnancy Outcome (HAPO) Follow-Up Study (FUS). Metabolic outcomes were assessed in children 10-14 years old following the HAPO pregnancy, comparing outcomes in offspring of mothers with gestational diabetes (GDM) diagnosed using International Association of Diabetes and Pregnancy Study Groups (IADPSG) criteria to those in offspring of mothers with normal glycemia during the HAPO pregnancy. Offspring of GDM mothers had a higher risk of obesity and greater adiposity. The association of GDM with childhood glucose outcomes was also examined. GDM was associated with higher levels of childhood 30-minute, 1-hour and 2-hour glucose levels during an oral glucose tolerance test as well as greater insulin resistance and a lower disposition index. Finally, GDM was associated with development of impaired glucose tolerance but not impaired fasting glucose during childhood. Similar to the linear association of maternal glucose with newborn outcomes in the HAPO Study, there was a similar linear relationship between maternal glucose levels and childhood adiposity and glucose outcomes. Finally, given the association of maternal hyperglycemia during pregnancy with a higher risk of macrosomia, the association of size at birth with childhood glucose outcomes was examined. After adjusting for maternal glucose levels, higher birthweight and newborn sum of skinfolds was associated with lower fasting and post-load glucose values during an oral glucose tolerance test as well as lower insulin sensitivity. In conclusion, offspring of mothers with GDM diagnosed using IADPSG criteria have higher glucose levels and greater adiposity at age 10-14 years, but the interplay between maternal metabolism during pregnancy, size at birth and childhood glucose outcomes is complex.