Needle and syringe programmes (NSPs) are effective, affordable solutions for preventing the transmission of blood-borne viruses among people who inject drugs. Yet, global NSP coverage remains extremely low; only 2% of people who inject drugs live in countries with high coverage, and many low-income and middle-income countries do not have NSPs. This Health Policy reports outputs from an international working group who used implementation science approaches to prioritise barriers and co-design solutions to scale up NSPs across three domains: global policy, national policy, and procurement. We present six barriers and 11 strategies that align commodity selection and procurement with the needs and preferences of people who inject drugs, strengthen national commitment and regulatory environments, and improve forecasting and market access for preferred products. We provide sector-specific actions for funders, governments, procurement agencies, implementers, community networks, and researchers. Scaling up NSPs is essential for achieving global infectious disease-elimination goals and improving health outcomes among people who inject drugs.