Purpose: Substance use disorder (SUD) frequently co-occurs with other psychological conditions, such as eating disorders (EDs). Psychological factors such as emotional dysregulation, rash impulsivity (RI) and reward sensitivity (RS) play a role in the etiology of each disorder, yet little is known about the combined effects of these on comorbid SUDs and EDs or disordered eating behaviours (DEBs). This study aims to examine the role of these psychological factors in comorbid DEBs and SUDs among individuals in treatment for SUDs. The role of gender is tested as a moderator. Design/methodology/approach: A cross-sectional self-report survey was completed by 131 participants attending Australian residential substance use treatment centres. A binomial logistic regression analysis was performed to examine the effects of emotional dysregulation, RI and RS on comorbid DEB and SUD. Further, moderation analyses were used to examine the moderating effect for gender on the relationship between these three personality variables and comorbidity. Findings: The most commonly reported primary substance of use was alcohol (43.5%), followed by amphetamines (38.6%). Findings showed that emotional dysregulation and RI were significantly related to an increase in comorbidity likelihood; however, RS was not. Gender moderated the relationship between comorbidity and RI only. Originality/value: The significant positive relationship found between RI and comorbidity for females only was a novel finding for the current study. Further research is needed to develop an understanding of the etiology of comorbidity.