The purpose of this scoping review was to map how gambling harms are measured in self-report questionnaires. Studies were included in the review if they measured gambling-related harms through self-reported questionnaires. Studies that used problem gambling measures, like the Problem Gambling Severity Index, as a proxy were also included. Overall, the researchers identified 41 different tools used to measure gambling harms across 131 studies. Most tools focused on financial, relationship, and mental health harms. Fewer assessed, crime, community and societal impacts. Overall, the researchers found differences across studies in the types of harms measured and how they were classified and scored. This highlights the need for researchers and practitioners to carefully select measurement tools based on their specific goals, populations, and contexts.