This study examines changes over time, and demographic differentials, in the prevalence of select sexual behaviors and contraceptive use measures in a national sample of US adolescents. We used data on female and male adolescents aged 15-19 from the 2006-2010 (N=4,662), 2011-2015 (N=4,134), and 2015-2017 (N=1,810) National Survey of Family Growth. Logistic regression was used to identify differences between periods by gender, and for some measures by age, in sexual behaviors (penile-vaginal intercourse (PVI), oral or anal sex with an opposite-sex partner, sexual experience with a same-sex partner), contraceptive use and condom consistency. We estimated probabilities of age at first PVI with Kaplan-Meier failure analysis and tested for changes over time and differences by gender. Over half of all adolescents have engaged in at least one of the sexual behaviors measured. Between 2011-2015 and 2015-2017, males age 15-17 reported significant declines in all but same-sex partners, while the prevalence of sexual behaviors among older males and adolescent females overall remained generally stable. In each period, females were more likely than males to report a same-sex partner. Age of first PVI increased, but by age 17 the difference between time periods is minimal. Adolescent females report increases in the use at last sex of long-acting reversible contraceptive methods (3% to 18%) and multiple methods (27% to 41%). The condom use measures did not change over time. These findings identify components of both stability and change in adolescent sexual and contraceptive behavior in the last decade. Implications This analysis contributes a timely update on trends in adolescent sexual behavior and contraceptive use, showing that adolescents’ behaviors are complex and evolving. Sexual health information and services must be available so that young people have the resources to make healthy and responsible choices for themselves and their partners.