The majority of the food insecurity-obesity research has indicated a positive association among women, especially minority women. Less research has been conducted on men, and the findings are inconsistent. The aim was to assess whether gender and race/ethnic disparities exists between the food insecurity and overweight/obesity relationship among adults ages 18–59. We used the cross-sectional 2011 and 2012 National Health Interview Survey data (N = 19,990). Three or more affirmative responses on the 10-item USDA Food Security Scale indicated food insecure experiences. Self-reported height and weight were used to calculate body mass index according to the Centers for Disease Control and Prevention. Multivariate logistic regression models were stratified by gender and race/ethnicity to estimate the association between food insecurity and overweight/obesity controlling for several demographic characteristics. Adults on average were 36 years of age (51% female; 56% white, 27% Hispanic, and 17% black), 27% were food insecure, and 65% were overweight/obese. Food insecurity was most prevalent among blacks and Hispanics, regardless of gender. A greater percentage of food insecure women were overweight/obese compared to food secure women among all race/ethnicity groups; while similar proportions of white, black, and Hispanic men were overweight/obese irrespective of their food security status. In covariate-adjusted models, food insecurity was associated with a 41% and 29% higher odds of being overweight/obese among white and Hispanic women, respectively. Food insecurity was not related to overweight/obesity among black women nor among white, black, and Hispanic men. The complex relationship between food insecurity and obesity suggests a need to investigate potential behavioral and physiological mechanisms, and moderators of this relationship.