Illicit drug use disorders are the most stigmatised health conditions worldwide, and stigma acts as a meaningful barrier to treatment entry and treatment provision. In the context of dramatically rising opioid-related harms, it is critical that we understand the drivers of stigma and how it affects opioid use disorder treatment and policy. The aim of this narrative review is to discuss how opioid-related stigma impacts treatment provision and harm reduction, and provide potential strategies to reduce stigma at a social and structural level. We used the Framework for Integrating Normative Influences on Stigma (FINIS) to identify sources of opioid-related stigma at the macro (structural stigma), meso (public stigma) and micro (internalised stigma) levels. Reducing stigma requires strategies that target multiple levels, however addressing inequity in the laws, regulations, and rules that segregate people with opioid and other substance use disorders from mainstream society is essential.