The substantial recent rise in opioid prescription rates, along with increasing evidence of misuse and associated morbidity and mortality, raises serious concerns about the appropri- ateness of these drugs for pain management. This study investigates prescription behaviour differences across opioid drug categories between UK-trained and overseas-trained GPs. Us- ing panel data covering all English practices from 2018 to 2021, we find a strong association between practices with more overseas GPs and opioid prescription patterns. Regional dif- ferences emerge, with GPs from North America prescribing more opioids and those from Africa and Asia prescribing less, relative to the UK-trained counterparts. Heterogeneous cultural norms, different training environments, and varying epidemiological patterns might explain these different prescribing behaviours. Comprehensive cross-country assessments of GP competencies could identify areas for targeted training, helping to align the practices of foreign-trained GPs with UK standards while supporting the attraction of global talent.