Background: The term intermittent fasting (IF), employed for health purposes or weight reduction, refers to many forms of caloric restriction. Insulin resistance has been recognized to ameliorate with fasting. Objective: This study aimed to evaluate the influence of IF on the occurrence of gestational diabetes mellitus (GDM) in overweight pregnant women during the third trimester and its implications for maternal and neonatal outcomes. Patients and Methods: A total of 278 obese pregnant women were divided into two groups: Group A included women who fast 16 successive hours daily including sleeping hours with all energy intake throughout the other eight hours window of the day. Group B included women who fast with the same life style. The study was conducted for 12 weeks. Maternal weight assessment was done just before delivery. Mode of delivery was reported. Screening of DM was done. Fetal assessment was done using Apgar score 1 and 5 mins and fetal weight at the time of the labor. Results: Intermittent fasting was accompanied by increased risk of occurrence of prediabetes, which was marginally statistically significant. However, effect on occurrence of GDM or the composite incidence of prediabetes and GDM was not statistically significant. Also, after adjustment for age and baseline BMI, there was no statistically significant effect of intermittent fasting and composite occurrence of GDM or prediabetes. Conclusion: Intermittent fasting in the 3rd trimester of pregnancy has no impact neither on the incidence of GDM in obese pregnant women nor maternal and neonatal outcomes.