Physical activity is strongly associated with health benefits in youth, although wide disparities in physical activity persist across sex, race/ethnicity, and income. Active transportation is an important source of youth physical activity. We aimed to describe active transportation patterns for United States adolescents and young adults ages 12–25 years across sociodemographic and weight status characteristics. Cross-sectional secondary data analyses were based on self-reported transportation-related physical activity using the National Health and Nutrition Examination Survey, 2007-2016. Of the sample (n = 8,680; population represented, N = 57,768,628), 4,300 (49.5%) were adolescents (12-17 y), and 4,380 (50.4%) were young adults (18-25 y). Male adolescents were more likely to participate in any (risk ratio RR = 1.3; 95% confidence interval CI, 1.16-1.40) and daily (RR = 1.3; 95% CI, 1.06-1.63) active transportation than females. Black (RR = 1.1; 95% CI, 1.01-1.31) and Hispanic (RR = 1.2; 95% CI, 1.05-1.31) adolescents were more likely to engage in any active transportation than whites. Young adult males were more likely to participate in any (RR = 1.3; 95% CI, 1.20-1.50) and daily (RR = 1.3; 95% CI, 1.08-1.55) active transportation than females. Young adults with a lower family income, and both adolescents and young adults with a lower household education, were more likely to engage in any and daily active transportation. We also observed an inverse relationship between weight class and active transportation participation. Active transportation was higher in males, minority, and lower income youth. Our study findings provide evidence for physical activity interventions, suggesting active transportation is a feasible target for low-income and minority youth to reduce physical activity disparities and support optimal health.