BACKGROUND AND OBJECTIVES: The objective of the current study is to evaluate the temporal trends in the prevalence of cigarette and electronic cigarette (e-cigarette) advertisement exposure by venue and sociodemographic correlates among US adolescents from 2012 to 2020. METHODS: We conducted a serial cross-sectional analysis of nationally representative samples of middle and high school youth from the 2012-2020 National Youth Tobacco Survey. Advertisement exposure was defined as self-report of seeing advertisements "sometimes," "most of the time," and "always." The prevalence of cigarette (and other tobacco products) and e-cigarette advertisement exposure, including overall and at specific venues (Internet, press, screen, and retail stores), was estimated by survey year. RESULTS: A total of 139 795 adolescents aged 11 to 19 years old were included in the analysis. The prevalence of exposure to combustible cigarette marketing remained high across all years (any venue ranging from 77.0%  to 91.1% ). An increasing trend for cigarette advertisement exposure was observed from 2017 to 2020 after a drop in 2015 (β2012-2015 = 2.8, P for trend < .001; β2017-2020 = .7, P for trend = .03), driven by retail store-based and Internetbased exposure. A similar increasing pattern in the estimated prevalence of e-cigarette marketing was observed (β2014-2016 = 4.6, P for trend < .001; β2017-2020 = 5.1, P for trend < .001). CONCLUSIONS: Given the high estimated prevalence of cigarette and e-cigarette marketing exposure among US adolescents, further regulation efforts for both off-line and online tobacco marketing are needed to mitigate adolescent exposure to content regarding these products, reducing susceptibility to uptake.