Comprehensive surveillance of e-cigarette use behaviors among youth is important for informing strategies to address this public health epidemic. To characterize e-cigarette use behaviors among US youth in 2020. The 2020 National Youth Tobacco Survey, a nationally representative, cross-sectional, school-based survey of middle school (grades 6-8) and high school (grades 9-12) students, was conducted from January 16, 2020, to March 16, 2020. A total of 14 531 students from 180 schools participated in the 2020 survey, yielding a corresponding student-level participation rate of 87.4% and school-level participation rate of 49.9%. The overall response rate, a product of the school-level and student-level participation rates, was 43.6%. Current (past 30-day) e-cigarette use. Self-reported current e-cigarette use behaviors (frequency of use, usual e-cigarette brand, and access source) by school level and flavored e-cigarette use and flavor types among current e-cigarette users by school level and device type. Prevalence estimates were weighted to account for the complex survey design. Overall, 14 531 students completed the survey, including 7330 female students and 7133 male students with self-reported grade level and sex. In 2020, 19.6% (95% CI, 17.2%-22.2%) of high school students and 4.7% (95% CI, 3.6%-6.0%) of middle school students reported current e-cigarette use. Among them, 38.9% (95% CI, 35.2%-42.6%) of high school users and 20.0% (95% CI, 16.0%-24.8%) of middle school users reported e-cigarette use on 20 to 30 days within the past 30 days. Among current users, JUUL was the most commonly reported usual brand (high school: 25.4%; 95% CI, 18.8%-33.4%; middle school: 35.1%; 95% CI, 27.9%-43.1%). Among current users, the most common source of obtaining e-cigarettes was from a friend (high school: 57.1%; 95% CI, 52.6%-61.4%; middle school: 58.9%; 95% CI, 51.4%-66.1%). Among current users, 84.7% (95% CI, 82.2%-86.9%) of high school students and 73.9% (95% CI, 66.9%-79.8%) of middle school students reported flavored e-cigarette use. Fruit-flavored e-cigarettes were the most commonly reported flavor among current exclusive e-cigarette users of prefilled pods or cartridges (67.3%; 95% CI, 60.9%-73.0%), disposable e-cigarettes (85.8%; 95% CI, 79.8%-90.3%), and tank-based devices (82.7%; 95% CI, 68.9%-91.1%), followed by mint-flavored e-cigarettes. These results suggest that although current e-cigarette use decreased during 2019 to 2020, overall prevalence, frequent use, and flavored e-cigarette use remained high. Continued actions are warranted to prevent and reduce e-cigarette use among US youth.