Based on data from the Financial Services Authority (OJK), the number of investors investing in the capital market is still relatively low when compared to the total population of Indonesia. The low interest in investing in the capital market is caused by a lack of financial literacy in investment instruments in the capital market. Financial literacy can be improved through Financial Socialization conducted by Socialization Agents consisting of family, peers, formal education, and the media. The object of this research is the millennial generation, because investing in stocks, has a relatively high risk, so it is estimated that the age that is resistant to anticipating high risk is the age of the millennial generation. The purpose of this research is to find out which socialization agent has the biggest role in the process of financial literacy. This research is quantitative research using primary data whose data is obtained by conducting a survey. This research found that media is the most influential agent of financial socialization on financial literacy in the millennial generation. The logical explanation is that the accessibility of media and the familiarity of internet-based media and social media for the millennial generation.