ABSTRACT Professionals’ understandings of substance use interventions and treatment goals impact treatment recommendations. We aimed to explore social work professionals’ (SWP) attitudes towards harm reduction philosophy and measures in three areas of Sweden with very differing development of their harm reduction: Malmö (most developed), Gothenburg (moderately developed), Gävleborg (least developed). We conducted a survey of SWP working with people who use drugs, utilizing the Harm Reduction Acceptability Scale (HRAS). An ANOVA with Bonferroni post-hoc correction was performed to assess for differences in mean HRAS score. There were 208 valid survey responses (Malmö: 79, Gothenburg: 82, Gävleborg: 47). The overall mean score indicated positive attitudes towards harm reduction. Means differed based on geographic location, with Malmö and Gothenburg scores indicating significantly more positive attitudes towards harm reduction than scores in Gävleborg. Opinions on implementation of new harm reduction measures such as heroin assisted treatment, supervised consumption sites, and decriminalization of drugs for personal use were more negative overall. These opinions followed the above trend, with regard to differences based on geography. Differences indicated that SWP who are more exposed to harm reduction have more positive attitudes. Increased knowledge of harm reduction among SWP could lead to improved access to interventions and reduced risks for people who use drugs.