We conducted a systematic review of racial, ethnic, and gender differences on financial knowledge in the United States. We reviewed journal publications that specifically study or consider racial, ethnic and gender differences in financial knowledge during the period 2010-2021. We include in this review a total of 33 papers, where nine focus on racial and ethnic differences, 14 focus on gender differences, and 10 consider racial, ethnic, and gender differences. From the reviewed studies, we estimate the average financial knowledge racial and ethnic gap, where Whites score on average 19 percentage points higher than Blacks, 14 percentage points higher than Hispanics, and 6 percentage points higher than Asians. We also estimate the average difference in financial knowledge between men and women, where men score 12 percentage points higher than women. Our review includes insights from previous work on three main areas: 1) How should stakeholders leverage research on financial knowledge, 2) How should financial education change, and 3) what directions should future research take