This study aimed to investigate the associations between substance use, gambling disorder, and addictive behaviors among individuals undergoing treatment in addiction rehabilitation camps in Bandar Abbas City. Employing a correlational design, all individuals receiving treatment at these centers were enrolled through a census sampling method, resulting in a sample of 210 participants. Data were collected using the Gambling Addiction Screening Questionnaire (GASQ), the Alcohol, Smoking and Substance Involvement Screening Test (ASSIST), the Hypersexual Behavior Inventory (HBI-19), and the Non-Prescription Drug Use Scale (NPDUS). The results of hierarchical regression indicated that for non-prescription medication use, substance use alone accounted for 12% of the variance (R² = 0.12), and the addition of gambling disorder significantly increased the explained variance (ΔR² = 0.09). For hypersexual behaviors, substance use alone explained only 4% of the variance (R² = 0.04), and the inclusion of gambling disorder did not yield a significant change (P > 0.05). The findings suggest that substance use and gambling disorder may serve as predisposing factors for non-prescription medication use. In the context of hypersexual behavior, substance use emerged as a more determinant factor. These findings may assist therapists and social workers in the field of addiction treatment to provide more active and targeted support to individuals undergoing treatment.