Gestational diabetes mellitus (GDM) is associated with fetal overgrowth and certain treatments are associated with an increased risk of macrosomia. However, there is limited data about the long-term effect of GDM treatment on childhood growth.Cohort study of 816 women with GDM and their offspring delivered between 2009-2012. Childhood height and weight through age 3 were collected from the medical record and Z-scores and body mass index (BMI) were calculated. We assessed the association between GDM treatment and childhood growth using linear mixed modeling.Treatment was divided into medical nutritional therapy (MNT) (n=293), glyburide (n=421), and insulin (n=102). At delivery, birthweight, z-score, and BMI were higher in the offspring of women treated with either glyburide or insulin compared to MNT. However, weight, z-score, and BMI were similar among all offspring at 6 months and 1, 2, and 3 years of age. After controlling for covariates, there were differences in the weight z-score (p=0.01) over the 3-year period by treatment group, but no differences in weight (p=0.06) or change in BMI (p=0.28). Pairwise comparisons indicated that insulin was associated with more weight gain compared to MNT (0.69 kg, 95% CI 0.10, 1.28, p=0.02) and glyburide was associated with a trend towards lower weight z-score compared to MNT (-0.24, 95% CI -0.47, 0.003, p=0.05).Despite growth differences detected at birth, we observed no meaningful differences in childhood growth from 6 months to three years among treatment groups, including in the offspring of women with GDM treated with glyburide.