Excessive gestational weight gain, particularly among overweight and obese women, is associated with adverse perinatal outcomes. Current interventions to limit gestational weight gain have achieved only modest success. We sought to improve adherence to gestational weight gain guidelines with a dual intervention of financial incentives and antenatal behavioral weight management. This was a prospective randomized controlled trial at a single academic medical center in which women were assigned randomly to the intervention group or standard care. The primary outcome was adherence to gestational weight gain guidelines. Secondary outcomes included total gestational weight gain, mode of delivery, birthweight, neonatal intensive care unit admission, and development of gestational diabetes mellitus and hypertensive disorders of pregnancy. A total of 136 women were assigned randomly, with data available for analysis of 124 women. Gestational weight gain within the Institutes of Medicine guidelines was similar (30% vs 29%) in the intervention and standard care groups, respectively. There were no statistically significant differences in total gestational weight gain or perinatal outcomes. There was a nonstatistically significant decrease in macrosomia in the intervention compared with standard care condition. A combined financial incentive and behavioral weight management intervention did not improve adherence to gestational weight gain guidelines. Modifications to the intervention may achieve improved results.