Aims/hypothesis Fried foods are frequently consumed in Western countries. However, the health effects of frequent fried food consumption in humans are not well understood. We aimed to prospectively examine the association between pre-pregnancy fried food consumption and risk of incident gestational diabetes mellitus (GDM). Methods We included 21,079 singleton pregnancies from 15,027 women in the Nurses' Health Study II cohort. Since 1991 and every 4 years thereafter, we collected diet information, including consumption of fried foods at home and away from home, using a validated food frequency questionnaire. We used generalised estimating equations with log-binomial models to estimate the RRs and 95% CIs. Results We documented 847 incident GDM pregnancies during 10 years of follow-up. After adjustment for age, parity, dietary and non-dietary factors, the RRs (95% CIs) of GD among women who consumed total fried foods 1-3, 4-6 and ≥7 times/week, compared with those who consumed it less than once/week, were 1.13 (0.97, 1.32), 1.31 (1.08, 1.59) and 2.18 (1.53, 3.09), respectively (p for trend <0.001). The association persisted after further adjustment for BMI (p for trend=0.01). When analysed separately, we found a significant association of GDM with fried food consumption away from home, but not with fried food consumption at home. Conclusions/interpretation Frequent fried food consumption, particularly away from home, was significantly associated with a greater risk of incident GDM. Our study indicates potential benefits of limiting fried food consumption in the prevention of GDM in women of reproductive age.