Many individuals with lifetime histories of eating disorders (EDs) report exposure to interpersonal trauma and posttraumatic stress disorder (PTSD). However, this relationship is not well-understood, and there are no established, evidence-based therapies for the concurrent treatment of EDs and PTSD. This review focuses on studies of the mechanisms associating trauma exposure and/or PTSD with EDs. Possible mechanisms of the trauma-ED association identified from the literature include self-criticism, low self-worth, guilt, shame, depression, anxiety, emotion dysregulation, anger, and impulsivity/compulsivity. ED behaviors may be used as coping strategies to manage PTSD symptoms and negative affect. Avoidance of hyperarousal symptoms by engaging in binge eating, purging, and/or restriction may serve to maintain both the ED as well as the PTSD. Given the evidence of the bidirectional relationship between EDs and PTSD, we describe an integrated cognitive behavioral theory that may account for the persistence of comorbid PTSD and EDs. The integrated model is based on the theoretical models that underpin existing evidence-based treatments for PTSD and ED and incorporates many of the potential mechanisms highlighted to date. The primary aim of the model is to identify potential treatment targets as well as elucidate future directions for research.