Interventions to promote healthy pregnancy in women with obesity by improving diet quality have been widely unsuccessful. We hypothesized that diet quality is determined by eating behaviors, but evidence in women with obesity is lacking. We evaluated diet quality and eating behavior in 56 women with obesity (mean ± SEM, 36.7 ± 0.7 kg/m², 46% White, 50% nulliparous) early in pregnancy (14.9 ± 0.1 weeks). Diet quality was objectively assessed with food photography over six days and defined by Healthy Eating Index. Eating behaviors were assessed by validated questionnaires. Women reported consuming diets high in fat (38 ± 1% of energy) and the HEI was considered “poor” on average (46.7 ± 1.3), and for 71% of women. Diet quality was independently associated with education level (p = 0.01), food cravings (p < 0.01), and awareness towards eating (p = 0.01). Cravings for sweets and fast foods were positively correlated with respective intakes of these foods (p < 0.01 and p = 0.04, respectively), whereas cravings for fruits and vegetables did not relate to diet intake. We provide evidence of the determinants of poor diet quality in pregnant women with obesity. Based on this observational study, strategies to improve diet quality and pregnancy outcomes are to satisfy cravings for healthy snacks and foods, and to promote awareness towards eating behaviors.