Background Inadequate sleep independently influences eating habits and weight status. However, the relationship between these three factors has not been well quantified. The objective of this study was to examine if eating behavior (i.e. dietary restraint, disinhibition and hunger) mediates the relationship between sleep and body mass index (BMI) in a large sample of American adults. Method Cross-sectional data from the Nathan Kline Institute Rockland sample were assessed (n = 602; 38.9 ± 14.5 years). Self-reported sleep and eating behavior were measured using the Pittsburgh Sleep Quality Index and Three Factor Eating Questionnaire, respectively. Path analysis was used to examine relationships amongst the construct, with mediation tested via bootstrapped confidence intervals. Results Poorer sleep quality was associated with both greater hunger (P = 0.03) and higher disinhibited eating (overeating in the presence of palatable foods or other disinhibiting stimuli like emotional stress; P < 0.001) behaviors. Higher disinhibited eating behavior was also associated with higher BMI (P < 0.001). There was a significant indirect relationship between sleep quality and BMI via disinhibition (b [95% CI] = 0.13 [0.06, 0.21], P = 0.001). No significant effects were found when total sleep time or time in bed were replaced as predictors in the mediation model. Conclusion Disinhibited eating behavior mediated the relationship between sleep quality and weight status in both males and females. This mediation was due to aspects of sleep quality other than duration. These results suggest that improving sleep quality may benefit weight loss by helping to reduce an individuals’ susceptibility to overeating.