Background <p>The relationship between gestational weight gain and perinatal outcomes in women with gestational diabetes remains inadequately studied, and specific weight gain recommendations are lacking for this population.</p> Methods <p>We conducted a retrospective cross-sectional study by extracting natality data from the National Center for Health Statistics (NCHS) of the Centers for Disease Control and Prevention in the United States, including 1,368,789 record (2015–2020) as the main sample and 280,165 (2021) as the validation sample. The composite adverse outcome is defined as a composite of gestational hypertension or preeclampsia, primary cesarean delivery, maternal transfusion, maternal intensive care admission, preterm birth&lt;37 weeks, small or large size for gestational age at birth and neonatal intensive care unit admission. Optimal gestational weight gain ranges were estimated for each pre-pregnancy body mass index category through multivariable logistic regression model to identify the odds ratio targets at which any adverse outcome decreased. Model discrimination was evaluated using area under the receiver operating characteristic curve.</p> Results <p>Adverse outcomes occur in 52.67% of pregnancies, with incidence rising substantially with body mass index (44.28% in normal weight vs 67.08% in class 3 obesity). The optimal gestational weight gain ranges are: underweight (12.0- &lt; 20.0 kg), normal weight (8.0- &lt; 16.0 kg), overweight (weight loss-&lt;14 kg), class 1 obesity (weight loss-&lt;10.0 kg) and obesity classes 2-3 (weight loss &lt;8.0 kg). These ranges demonstrate low to moderate discrimination between affected and unaffected pregnancies (ranges of area under the receiver operating characteristic curve, 0.57–0.68).</p> Conclusions <p>Minimal weight gain or weight loss is associated with a decreased risk of adverse perinatal outcomes among women with overweight or obesity complicated by gestational diabetes.</p>