People who have experienced sexual assault (SA) often have problems with disordered eating (DE). However, little is known about why this is the case. One possible explanation is that SA changes the functions (or motivations for) DE. Using a previously established four-function model of behavior (identifying automatic negative, automatic positive, social negative, and social positive reinforcement functions), this study investigated whether the functions of DE are different in those who have been sexually assaulted, as compared to those who have not been sexually assaulted. Secondary analyses aimed to establish relationships between the functions of DE and sexual objectification, shame, guilt and self-blame. Participants were 187 adults of all genders living in the United States, all of whom engage in DE. Of these participants, 126 reported at least one instance of SA. We assessed the functions of DE, sexual objectification, shame, guilt and self-blame through self-report questionnaires. The four-factor model was not a good fit for the data. However, a multigroup factor analysis revealed significant differences between the SA and non-SA groups with respect to the functions of DE. Compared to those with no history of SA, individuals with a history of SA were more likely to endorse engaging in DE for reasons relating to social negative reinforcement (e.g., to avoid social interactions). This difference may be driven by a desire to reduce sexual objectification, and this relationship remained significant even after controlling for history of other forms of trauma. Future studies should attempt to parse the functions of different types of DE in the context of SA, as well as establishing potential differences between SA-induced-DE and DE that predates SA. Implications for treatment are discussed.