© 2017 AGA Institute Background & Aims Sex and sex hormones can affect responses of patients with nonalcoholic fatty liver disease (NAFLD) to metabolic stress and development of hepatocyte injury and inflammation. Methods We collected data from 3 large U.S. studies of patients with NAFLD (between October 2004 and June 2013) to assess the association between histologic severity and sex, menopause status, synthetic hormone use, and menstrual abnormalities in 1112 patients with a histologic diagnosis of NAFLD. We performed logistic or ordinal logistic regression models, adjusting for covariates relevant to an increase of hepatic metabolic stress. Results Premenopausal women were at an increased risk of lobular inflammation, hepatocyte ballooning, and Mallory-Denk bodies than men and also at an increased risk of lobular inflammation and Mallory-Denk bodies than postmenopausal women (P <.01). Use of oral contraceptives was associated with an increased risk of lobular inflammation and Mallory-Denk bodies in premenopausal women, whereas hormone replacement therapy was associated with an increased risk of lobular inflammation in postmenopausal women (P <.05). Conclusions Being a premenopausal woman or a female user of synthetic hormones is associated with increased histologic severity of hepatocyte injury and inflammation among patients with NAFLD at given levels of hepatic metabolic stress.