Success in the current complex and sophisticated financial marketplaces depends on the ability of people to make sustainable financial decisions to improve their future well-being, for which financial literacy is a pathway. This study examines the relationship between the demographic and socio-economic factors and financial literacy in Japan by segregating financial literacy into financial knowledge, attitude, and behavior, and providing a deeper understanding of the relationships. The methodology included using data from the Financial Literacy Survey 2016 by the Central Council for Financial Services Information of Japan. We used a linear regression model to explain how demographic and socio-economic factors relate to financial knowledge, attitude, and behavior. Results show that education, the balance of financial assets, and the use of financial information are positively related, while the experience of financial trouble is negatively related to financial knowledge, attitude, and behavior. We show that males are more financially knowledgeable than females, but females are more positive than males with regard to financial behavior and financial attitude. Age is positively related to financial knowledge but negatively related to financial attitude, thus suggesting that middle-aged people in Japan are more financially knowledgeable, but younger and older people are more positive with regard to financial behavior and attitude. The findings have implications for policymakers.