This evidence brief examined the impact of the COVID-19 pandemic on drug services in New South Wales, Scotland, New York State and British Columbia. These jurisdictions were chosen because they are developed economies, have been disrupted by the COVID-19 epidemic, and official documentation is available in English. They also have patterns of problem drug use similar to Ireland and provide a comparable range of treatment and harm reduction responses. The evidence brief also presents a summary of information available in Ireland and in other countries in the European Union to provide a context beside which findings from the four research countries can be read.