GameSense is a responsible gambling (RG) initiative that seeks to educate people who gamble about how to gamble safely. GameSense was adopted by MGM Resorts International (MGM) at its US-based properties in 2017. The authors of this study sought to investigate whether GameSense has been effective in promoting healthy gambling beliefs and use of RG strategies. They also wanted to know whether GameSense efficacy differed depending on the type of property. MGM administered a survey to its loyalty members three times across approximately three years. The researchers found that few people were aware of or engaged with GameSense. Awareness of GameSense increased from before its implementation to one year after it was implemented. Awareness of GameSense did not increase the following year. Additionally, people aware of GameSense used slightly more RG strategies than those not aware of GameSense. Engagement did not increase over the years.