Purpose <p>Older cancer survivors have concerning rates of unsafe opioid prescribing. Little is known about the specialty of providers prescribing to survivors, which is essential to guide interventions.</p> Methods <p>Using SEER-Medicare data, we identified adults age &gt; 65 diagnosed 2014–2017 with stage I–III female breast, lung, or colorectal cancer with ≥6&#xa0;months treatment-free follow-up through 2019. Each opioid filled after treatment completion was assigned to a prescriber specialty: oncology, surgery, primary care, pain medicine, or other. Generalized estimating equation models captured the relative likelihood of an opioid being prescribed by each provider specialty.</p> Results <p>Among 69,769 survivors, 46% of breast, 49% of colorectal, and 49% of lung cancer survivors filled ≥1 opioid prescription during follow-up. For all three cancers, primary care providers (PCPs) prescribed a greater share of opioid fills (50%–56%) than other specialists, prescribed opioids to a greater share of survivors (49%–56%) than other specialists, and prescribed opioids for longer durations (median 30&#xa0;days/year) than oncologists and surgeons. The likelihood of an opioid being prescribed by an oncologist was up to 9 times lower than that of it being prescribed by a PCP: probability ratios 0.11 (95% CI 0.10–0.13) for breast, 0.12 (95% CI, 0.10–0.14) for colorectal, and 0.15 (95% CI, 0.13–0.17) for lung cancer survivors.</p> Conclusion <p>PCPs are highly involved in prescribing opioids to older survivors of common cancers. Interventions to enhance pain management for survivors should target primary care.</p> Implications for Cancer Survivors <p>As survivors transition away from oncology-based care, oncologists must communicate with PCPs about ongoing pain and opioid prescribing.</p>