Numerous studies have demonstrated an association between maternal obesity and the risk of stillbirth. However, the magnitude of association varies across study population. The objective of this study is to examine the risk of stillbirth with increasing severity of obesity and to examine the impact at varying gestational lengths. This was a retrospective cohort analysis of singleton non-anomalous births using the updated Texas vital records database between 2006 and 2014. Analysis were stratified based on maternal pre-pregnancy BMI into normal, overweight and obesity classes I, II, III as well as super obesity (BMI≥50 kg/m2). Gestational age was stratified into the following four periods for analysis: 24-33 weeks, 34-36 weeks, 37-40 weeks and 40-42 weeks. The risks of stillbirth associated with each BMI class was compared to normal weight pregnancies for each gestational period using proportional hazard regression models. The regression models were adjusted for potential confounders. After all exclusions 3,279,846 births remained for analysis, including 11,023 stillbirths (3.4 per 1,000 births). Compared to normal weight pregnancies, the risk of stillbirth increased with increasing BMI at term. Between 37-39 weeks, the risk of stillbirth compared to normal weight group was HR: 1.36 [1.19, 1.54] in the overweight group, and HR: 2.29 [1.26, 4.16] in the super obesity group. Between 40-42 weeks, the risk of stillbirth compared to normal weight group was HR: 1.42 [1.08, 1.86] in the overweight group and 5.84 [2.15, 15.85] in the extreme obesity group. Obesity remains one of the major risk factors of term stillbirth. There appears to be a dose-response effect leading to an increasing risk of stillbirth overall with increasing BMI classes. The high risk of stillbirth associated with extreme obesity between 40-42 weeks necessitate prospective studies on the risks and benefits of earlier delivery of pregnancies with this risk factor.