To minimize the harms associated with gambling, an array of responsible gambling (RG) messages has been developed to raise awareness of the risks of problem gambling and encourage safer gambling behaviors. However, evidence is limited as to the utility of RG messages to promote positive gambling-related beliefs and behaviors. In the current paper, we report the results of a Rapid Evidence Assessment (REA) of empirical research on RG messages. We identified 3200 unique articles published between 1890 and September 2024 using search terms related to RG messaging. Eighteen articles (containing 20 unique studies) met our inclusion criteria. Two general themes emerged: 1) RG message preferences among players and 2) RG message effectiveness. Specifically, players prefer self-appraisal messages, which were more effective in promoting RG behaviors compared to informative messages. Messages content also needs to be segmented (i.e., low-risk players prefer different types of messages than high risk players, such as highlighting player quizzes for low-risk players and helplines for high-risk players). Lastly, RG messages should be presented dynamically (e.g., pop-ups on an Electronic Gaming Machine: EGM). Results suggest a need for the gambling industry to adopt targeted, evidence-based RG messaging, as well as a need to engage in integrated knowledge mobilization, to more effectively promote RG. These findings underscore the importance of tailoring RG messages to player risk levels and preferences while leveraging dynamic delivery methods to maximize their effectiveness in promoting safer gambling behaviors and reducing harm.