BACKGROUND AND OBJECTIVES: Socioeconomic disparities in cardiovascular health among adults have been documented, but disparities during adolescence are less understood. In this study, we examined secular trends in 7 cardiovascular risk factors and disparities among US adolescents. METHODS: We analyzed NHANES data from 1999 to 2014, including 11 557 (4854 fasting) participants aged 12 to 19 years. To examine trends in cardiovascular risk factors, adolescents were stratified into 3 groups on the basis of family poverty-income ratio: low income (poverty-income ratio, <1.3), middle income (≥1.3 and <3.5), and high income (≥3.5). RESULTS: From 1999 to 2014, the prevalence of obesity increased (16.5%-21.0%, P = .001) but only among low-and middle-income adolescents, with significant disparities in prevalence by income (21.7% vs 14.6% among low-versus high-income adolescents, respectively, in 2011-2014). In addition, there were significant and persistent disparities in the prevalence of smoking (20.8% vs 7.4% among low-versus high-income adolescents, respectively, in 2011-2014), low-quality diet (67.8% vs 49.0%), and physical inactivity (25.6% vs 17.0%). No significant disparities were observed in the prevalence of prediabetes and diabetes, hypertension, or hypercholesterolemia, although the prevalence of prediabetes and diabetes increased among low-income adolescents (21.4%-28.0%, P = .01). Overall, the prevalence of adolescents with 2 or more risk factors declined (48.3% to 37.1%, P<.001), but this decline was only significant for high-and middle-income adolescents. CONCLUSIONS: Recent improvements in cardiovascular health have not been equally shared by US adolescents of varying socioeconomic status.