Excessive postpartum weight retention conveys risks for future metabolic diseases. Eating behaviors influence postpartum weight retention; however, the modifiable predictors of eating behaviors remain unclear. Using data from a three-arm, randomized controlled trial, the purpose of this study was to examine the longitudinal associations of mental health (e.g., depressive symptoms) and behavior change skills (e.g., self-efficacy) with eating behaviors (i.e., compensatory restraint, routine restraint, emotional eating, and external eating) among women (N = 424) over 18-months postpartum. Results revealed that depressive symptoms, perceived stress, healthy eating self-efficacy, overeating self-efficacy, self-weighing, and problem-solving confidence were associated with one or more of the examined eating behaviors. Furthermore, depressive symptoms moderated the association between healthy eating self-efficacy and routine restraint. Perceived stress moderated the associations between healthy eating/overeating self-efficacy and emotional eating. The findings suggest that mental health and behavior change skills may serve as targets for interventions designed to improve postpartum women’s eating behaviors. Clinical trials registry:ClinicalTrials.gov #NCT01331564