Alcohol consumption throughout pregnancy can cause metabolic dysregulation, including glucose intolerance in progeny. This study determined if periconceptional (PC) alcohol (12% v/v in a liquid diet) (PC:EtOH) consumed exclusively around conception results in similar outcomes in Sprague‐Dawley rats. Control (C) rats were given a liquid diet containing no alcohol but matched to ensure equal caloric intake. PC maternal alcohol intake (from 4 days before conception until day 4 of gestation), resulted in offspring with elevated fasting plasma glucose (~10–25%, P < 0.05), impaired glucose tolerance (P < 0.05), and decreased insulin sensitivity (P < 0.01) at 6 months of age. This was associated with increased hepatic gluconeogenesis and sex‐specific alterations in peripheral protein kinase B (AKT) signaling. These changes were accompanied by increased mRNA expression of DNA methyltransferases (DNMTs) 1, 3a, and 3b (1.5‐ to 1.9‐fold, P < 0.05) in fetal liver in late gestation, suggesting PC:EtOH may cause epigenetic changes that predispose offspring to metabolic dysfunction. Exposure to a postnatal (PN) high‐fat and cholesterol diet (HFD) from 3 months of age caused hyperinsulinemia (~2‐fold increase, P < 0.001) and exacerbated the metabolic dysfunction in male offspring exposed to PC:EtOH but had no additive effects in females. Given many women may drink alcohol while planning a pregnancy, it is crucial to increase public awareness regarding the effects of alcohol consumption around conception on offspring health.—Gårdebjer, E. M., Anderson, S. T., Pantaleon, M., Wlodek, M. E., Moritz, K. M. Maternal alcohol intake around the time of conception causes glucose intolerance and insulin insensitivity in rat offspring, which is exacerbated by a postnatal high‐fat diet. FASEB J. 29, 2690–2701 (2015). www.fasebj.org