Background: Around 12% of pregnant women develop gestational diabetes mellitus (GDM), which is associated with increased health risks for both mother and child and pre- and postpartum depression. Little is known about the relationship of GDM with diabetes-specific emotional distress (diabetes distress). The aims of this study are to assess the prevalence of diabetes distress in GDM and its association with adverse pregnancy outcomes. Methods: A prospective cohort study was carried out in an Amsterdam based teaching hospital with an ethnic diverse population. Women diagnosed with GDM completed a set of questionnaires at three time points. Questionnaires consisted of Problem Areas in Diabetes Scale 5 (PAID-5) for diabetes distress (T0-T1), Patient Health Questionnaire 9 (PHQ-9) for depressive symptoms (T0-T2), and questions to assess adverse pregnancy outcomes (T2). Adverse pregnancy outcomes (collected via self-report and if feasible from the medical records) were defined as hypertension, pre-eclampsia, caesarean section, severe perineal tearing, postpartum hemorrhage, postpartum depression, shoulder dystocia, neonatal hospitalization, macrosomia, jaundice, hypoglycemia and other (among which low heart rate, fever, hypoxia). Adverse pregnancy outcomes were dichotomized into none and 1 or more. Additional information was collected from the medical charts. Missing data were imputed via predictive mean matching and a multivariable logistic regression analysis was performed with diabetes distress, depressive symptoms, socioeconomic status, parity and ethnicity as predictors and age, HbA1c, and BMI as covariates. Results: A total of 100 women were included, mean age 32.5 (4.1), mean BMI 26.7 (4.8), 71% were of non-Dutch ethnic background. Elevated diabetes distress (PAID score ≥ 8) was reported by 36% of the women. Multivariable logistic regression analyses revealed that both high diabetes distress (OR 4.70, p =.02) and parity (OR 0.21, p =.02) but not antepartum depressive symptoms were related to adverse pregnancy outcomes. Conclusions: Diabetes distress is likely in women with GDM and our findings suggest an association between both diabetes distress, parity and adverse pregnancy outcomes in women with GDM. This warrants replication and further research into the underlying mechanisms explaining the impact of diabetes distress in GDM and potential interventions to reduce distress.