Background: The role of serum ferritin in predicting pregnancy outcomes among women with gestational diabetes mellitus (GDM) remains incompletely understood.Objective: To evaluate the association between serum ferritin levels and adverse pregnancy outcomes in women with GDM. Methods: This prospective observational study included 126 pregnant women diagnosed with GDM. Serum ferritin levels were measured at diagnosis, and participants were followed until delivery. Maternal and neonatal outcomes were analyzed in relation to ferritin levels. Results: The mean serum ferritin level was 85.6 ± 42.3 ng/mL, with 19.9% of participants showing elevated levels (>150 ng/mL). Significant positive correlations were observed between ferritin levels and glycemic parameters (HOMA-IR: r=0.51, p<0.001). Women with elevated ferritin levels demonstrated higher rates of pregnancyinduced hypertension (24.0% vs 9.0%, p=0.042), preeclampsia (16.0% vs 5.6%, p=0.038), and cesarean delivery (56.0% vs 34.8%, p=0.045). Neonatal complications, including macrosomia (32.0% vs 13.5%, p=0.028) and NICU admission (24.0% vs 10.1%, p=0.035), were significantly higher in the high ferritin group. Conclusion: Elevated serum ferritin levels are associated with increased risk of adverse maternal and neonatal outcomes in GDM patients, suggesting its potential utility as a predictive biomarker.