This study explored the practices and strategies of ambush marketing via social media (SM) during the 2014 Sochi, 2016 Rio, and 2018 PyeongChang Olympic Games. An observational netnography method was adopted to investigate direct industry competitors’ (of the Olympic sponsors) use of SM for the purpose of ambush marketing during the 2014, 2016, and 2018 Games. Data were gathered from the official Twitter accounts of 15 direct industry competitors over the three most recent Games. Despite a series of SM guidelines released by IOC for the 2014, 2016, and 2018 Games, the findings showed that the practice of ambush marketing via SM was evident during each of the Games. Direct industry competitors were found employing four specific ambush strategies, namely, associative, values, coattail, and property infringement. Theoretical and practical implications, as well as an impetus for future research, are suggested.