Context: Long-term use of prescribed opioids for the management of chronic pain in the primary care setting in Australia is associated with opioid dependence. This is often undiagnosed and untreated, with attendant harms.Objectives: This research sought to analyse Australian GPs’ intention to diagnose and manage opioid dependence in their patients’ prescribed opioids for chronic pain and understand how this may have changed over time.Methods: This longitudinal theory-based qualitative research used repeated semi-structured interviews with 24 GPs working in New South Wales, Australia. We analysed GP intention to diagnose and manage opioid dependence in their patients’ prescribed opioids for the management of chronic pain through the three factors of the Theory of Planned Behaviour: attitude, social norms and behavioural controls. We also assessed the impact on intention due to time, programs, policies, and other incentives that occurred between 2021 and 2023.Results: Theory of Planned Behaviour factors affected GPs’ engagement in opioid dependence diagnosis and management. Experience of fruitful conversations with patients regarding opioids, pain and risk strengthened positive attitudes. Patients expressing a desire to change opioid use due to opioid risk concerns and colleagues who diagnosed and managed opioid dependence built positive social norms for participants. Education, increased skills, real-time prescription monitoring tools, changes to government funding and approval of medications, collegial support and workplace increased positive behavioural controls. Difficult, futile conversations with patients, adverse regulatory experiences, isolation, and perceived imperative to shift care to specific monitored medicine programs decreased intention. Covid had an impact, and over the study period, many participants chose to decrease or cease general practice.Discussion: Positive attitudes, social norms and behavioural controls may increase GPs’ intention to diagnose and manage opioid dependence in their chronic pain patients.Conclusions: Programs and initiatives that consider and build positive attitudes, social norms and behavioural controls may assist GPs to better manage opioid use, including deprescribing or opioid dependence treatment in their chronic pain patients, potentially with better treatment outcomes. Current funding limitations in Australian general practice must be addressed.