Objective: To assess gestational diabetes mellitus (GDM) awareness among women in the Northern Borders Province of Saudi Arabia and identify factors associated with knowledge levels. Methods: A cross-sectional study was conducted among 461 women using a structured, validated online questionnaire assessing demographics, medical history, and knowledge of GDM’s effects on maternal and neonatal outcomes. Associations between demographic factors and GDM awareness were analyzed using chi-square tests. Results: Most participants (98.5%) were Saudi nationals, with a mean age of 34.5 ± 10.0 years; 82.6% had university-level education. Overall, 42.3% demonstrated fair awareness of GDM, 34.3% had good awareness, and 23.4% had poor awareness. Knowledge of GDM’s maternal complications varied: 70% recognized the risk of emergency cesarean section, but only 8.2% were aware of increased preeclampsia risk. For neonatal outcomes, 58.4% identified high birth weight as a risk, while only 31.9% recognized the risk of congenital anomalies. Higher awareness was significantly associated with education level (p = 0.02), pregnancy status (p = 0.001), trimester (p = 0.002), and family history of relevant conditions (p = 0.04). Conclusion: Although many women showed fair-to-good awareness of GDM, notable gaps remain, especially regarding specific complications. Targeted educational interventions, particularly for less-educated and non-pregnant women, are recommended to improve GDM awareness and pregnancy outcomes.