This study examines the relationship between the age at menarche and gestational diabetes mellitus (GDM). This retrospective study included subjects who were diagnosed with GDM at a pregnancy polyclinic in Kocaeli, Turkey between 2014 and 2018. The mean ages at menarche were 12.6 and 13.03 years in the GDM group and control group, respectively. The analysis results showed that pre-pregnancy cycle duration, age at menarche and pre-pregnancy BMI are statistically significant in terms of the development of gestational diabetes. (p < .05).In our study showed that the risk of GDM was found to be 2.3 times higher in pregnant women with a menarche age of <12 years. If the pre-pregnancy BMI value is more than 25 kg/cm(2), the risk of GDM was found to be approximately 2 times higher. The study indicated that age at menarche, cycle duration, and BMI were risk factors for GDM. IMPACT STATEMENT What is already known on this subject? GDM has a lasting health impact on both the mother and the foetus. While several risk factors have previously been identified for GDM such as family history, obesity, advanced maternal age, significant gaps remain in our understanding of the risk factor and pathogenesis. Recent studies suggested that earlier menarche was significantly associated with an increased risk of GDM. What do the results of this study add? There might be ethnic differences on the relationship between the GDM and menarche age. There is no study examining the relationship between the age of menarche and GDM in Turkey. In presented study, we determined the risk factors of GDM including the age of menarche, cycle duration and BMI. What are the implications of these findings for clinical practice and / or further research? Therefore, a comprehensive evaluation of the menstrual history by healthcare professionals is important for future pregnancy risks. It is important to understand risk factors for GDM and to establish preventive strategies among high-risk populations. In addition, this study will shed light on future epidemiological and cohort studies.