The growth of electronic money transactions in Indonesia at 2019 increased by 230.25% and making any financial enterprise technology (fintech) more competing. Digital Payment OVO Instagram used social media to expand their marketing activities, thus forming a digital communication between companies and customers. Communication is a form of Electronic Word Of Mouth Activity (EWOM)in social media. The purpose of this study to determined how big electronic word of mouth on social media Instagram influence brand loyalty OVO. This study was conducted using a quantitative approach through surveys. The survey was conducted using questionnaires distributed online to the respondents through social media. The measurement clarified by eight dimensions: quality EWOM, quantity EWOM, Sender expertise, Measures behavior, switch cost, satisfaction, linking Brand, And commitment. The population of OVO users by 2019, amounting to 115 million people and 100 people into the sample by using the formula Taro Yamanewith a confidence interval of 90%. The sampling technique used purposive sampling. Based on the results of research and data analysis has been done, the obtained results that electronic word of mouth has a contribution of 32.8% in an effort to influence the Brand Loyalty OVO. The rest 67.2% is made up of the effects and influence of other factors outside of this study.