This paper reviews what we have learned about financial literacy and its relationship to financial decision-making around the world. Using three simple questions, we have surveyed people in many countries to determine whether they have the fundamental knowledge of finance needed to function as effective economic decision makers. We show that levels of financial literacy are low not only in the United States, but also in many other countries, including those with well-developed financial markets. Moreover, financial illiteracy is particularly acute for some demographic groups, especially women and the less-educated. These findings are important since financial literacy is linked to borrowing, saving, and spending patterns. We also offer new evidence on financial literacy among high school students, drawing on the newly-released Programme for International Student Assessment implemented in 18 countries. Last, we discuss the implications of this research for policy.