Background: Gestational diabetes mellitus (GDM) is a leading cause of perinatal morbidity and mortality globally. Currently, the screening and diagnosis of GDM is based on a 2-hour 75 g Oral Glucose Tolerance Test (OGTT). This test cannot be performed on all pregnant women because of social, cultural and economic constraints. There have been suggestions on the use of clinical risk factors and the risk factors-based models as alternatives. These have not been widely tested especially in low-resource countries. Objectives: This study aimed to determine the accuracy of the clinical risk factors and to evaluate the performance of established clinical risk factor-based models as screening tool for GDM using the 2 hour 75g OGTT as the gold standard. Methodology: This cross-sectional study was conducted at the Obstetrics Units of the Department of Obstetrics and Gynaecology, Lagos State University Teaching Hospital, Ikeja, Lagos. Consecutive consenting 400 pregnant women that had their first antenatal clinic and had their weight and height measured and recorded at a gestational age less than or equal to 24 weeks were recruited for the study. Information on socio-demographic characteristics and obstetrics history was obtained. All the study subjects were also assessed using three different clinical risk-based models. When these women were within gestational age 24-28 week, venous blood sample and urine were collected for random blood glucose test and glucose test respectively. The women were also requested to return for a fasting 2-hour 75g OGTT. Glucose estimation was done using enzymatic reaction of oxidase-peroxidase method. Statistical analysis was done using the statistical package for social science (SPSS) version 24. The Receiver Operating Curve (ROC) was used to determine the accuracy of the risk factor-based models.