Background: Patients rarely dispose of left-over opioids after surgery. Disposal serves as a primary prevention against misuse, overdose, and diversion. However, current interventions promoting disposal have mixed efficacy. Increasing disposal in rural communities could prevent or reduce the harms caused by prescription opioids. Aims: Identify barriers and facilitators to disposal in the rural communities of the United States Mountain West region. Methods: We conducted a qualitative description study with 30 participants from Arizona, Idaho, Montana, Nevada, Oregon, Utah, and Wyoming. We used a phronetic iterative approach combining inductive content and thematic analysis with deductive interpretation through the Precaution Adoption Process Model (PAPM). Results: We identified four broad themes: (a) awareness, engagement, and education; (b) low perceived risk associated with nondisposal; (c) deciding to keep left-over opioids for future use; and (d) converting decisions into action. Most participants were aware of the importance of disposal but perceived the risks of nondisposal as low. Participants kept opioids for future use due to uncertainty about their recovery and future treatments, breakdowns in the patient-provider relationship, chronic illness or pain, or potential future injury. The rural context, particularly convenience, cost, and environmental contamination, contributes to decisional burden. Conclusions: We identified PAPM stage-specific barriers to disposal of left-over opioids. Future interventions should account for where patients are along the spectrum of deciding to dispose or not dispose as well as promoting harm-reduction strategies for those who choose not to dispose.