Paying credit card, mortgage, or student loan debt late damages a person’s financial health. This brief uses the 2015 FINRA Foundation National Financial Capability Study data to estimate the relationship between financial knowledge and past-due credit card, mortgage, and student loan debt. According to our analysis, financially knowledgeable adults are less likely to be past due on credit card, mortgage, or student loan payments. Adults who answered four or five questions correctly on a five-question financial knowledge quiz, compared with similar adults who answered zero or one question correctly, were 8.3 percentage points (45 percent) less likely to have been past due on a credit card payment, 15 percentage points (56 percent) less likely to have been past due on a mortgage payment, and 11 percentage points (41 percent) less likely to have been past due on a student loan payment in the previous 12 months. In addition, financial knowledge is often a more reliable predictor of past-due payment rates than consumer characteristics such as educational attainment, age, race or ethnicity, and gender. For example, consumers with a college degree were only 1.2 percentage points (8 percent) less likely to have been past due on a credit card payment than similar adults with a high school diploma or less education.