Introduction: Gestational diabetes is defined as various degrees of glucose intolerance diagnosed or detected for the first time during pregnancy and is the most common metabolic complication of pregnancy. Early diagnosis and adequate treatment are important to prevent complications. Pre-eclampsia, polyhydramnios, fetalmacrosomia, and operative delivery are some of the complications seen in pregnant women diagnosed with Gestational Diabetes Mellitus (GDM). Aim: The present study was designed to determine whether there was an association between Mean Platelet Volume (MPV) in predicting poor fetal outcome, insulin resistance, neonatal Apgar scores and gestational age for women with GDM. Materials and Methods: In this retrospective study, we enrolled 101 pregnant women with GDM together with a group of 138 healthy controls. MPV, insulin and homeostatic model assessment (HOMA-IR) values were measured at 24-28 weeks of the pregnancy. An independent samples t-test was used to compare MPV values. Multivariate linear regression models were used to establish relations between MPV values, HOMA-IR, insulin levels and Apgar score. Results: There was a significant positive correlation between MPV values, HOMA-IR and insulin levels and a negative correlation with Apgar score at 1 min and 5 min in the GDM group (r=0.227, p=0.02; r=0.206, p=0.03; r=-0.485, p<0.001; and r=-0.399, p<0.001, respectively). In the multivariate logistic regression analysis, a high MPV value was most consistently associated with a low Apgar 1 min score (β=-0.387, p=0.003) in the GDM group. An MPV of >8.0 fL had a sensitivity of 82% and a specificity of 75% for the prediction of GDM. Conclusion: We investigated the potential of MPV values in predicting low Apgar scores and insulin resistance in women with GDM.