Objectives: Some studies show an increased risk of gestational diabetes mellitus for ABO blood groups. Others find a lower risk or do not identify any association. Inconsistencies may be due to the heterogeneity in the control for confounding variables. We determined the association between ABO blood groups and gestational diabetes mellitus in Mexican women, controlling for gravidity and age, pre-pregnancy body mass index, fasting glucose at the first trimester, and first-degree relative with diabetes. Methods: This case-control study was conducted from February 2019 to December 2021 in Monterrey, Mexico, with 185 cases (women with gestational diabetes mellitus) and 530 controls. ABO blood groups and other variables were obtained from the clinical records. A multivariate binary logistic regression was used for estimating association. Two models were run, one for primigravidae and another for non-primigravidae. A p-value < 0.05 was significant. Results: The ABO blood groups were O (69.4%), A (22.2%), B (6.7%), and AB (1.7%), with no differences between cases and controls (p = 0.884). No association was found between ABO blood groups and gestational diabetes mellitus, in primigravidae or non-primigravidae. Conclusion: ABO blood groups were not associated with an increased risk of gestational diabetes mellitus in Mexican women, independent of gravidity and well-known risk factors. Copyright: © 2023 Cordero-Franco et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.