BackgroundThe lawsuit that led to the U.S. Master Settlement Agreement (MSA) exposed the cigarette industry’s deceptive marketing practices, which changed population perceptions about the cigarette industry and helped prevent cigarette smoking. The cigarette industry now owns many electronic cigarette (e-cigarette) companies and make their own e-cigarettes. Given that the MSA occurred in previous decades, many millennial and generation Z young adults may not know about the MSA and the cigarette industry’s marketing practices. It is unknown whether awareness about the MSA and cigarette industry practices may influence these young adults’ e-cigarette industry and e-cigarette health risk perceptions, which may inform e-cigarette prevention efforts.MethodsCross-sectional data were collected from a U.S. sample of tobacco-naïve young adults, 18–30 years-old, susceptible to e-cigarette use (n = 1,329) through an online panel service in August 2021-January 2022. Participants reported their demographic characteristics, awareness of the MSA, awareness of cigarette industry practices, e-cigarette industry perceptions, and e-cigarette health risk perceptions. We examined the relationships between awareness of the MSA and cigarette industry practices with e-cigarette industry and e-cigarette health risk perceptions using multivariable linear regressions, adjusted for demographic characteristics.ResultsOverall, 36.2%, 24.1%, and 39.3% of participants had heard of the MSA and knew a lot about it, had heard of the MSA, but did not know much about it, and did not hear of the MSA, respectively. On average, participants were aware of 5.2 (SD = 3.0) of the 11 cigarette industry practices included. Hearing about the MSA and knowing a lot about it and awareness of more cigarette industry practices were associated with less positive e-cigarette industry and higher e-cigarette health risk perceptions, whereas having heard of the MSA but not knowing much about it was associated with more positive e-cigarette industry and lower e-cigarette health risk perceptions.ConclusionsFindings suggest that increasing comprehensive awareness of the MSA and cigarette industry practices may influence young adults’ e-cigarette-related perceptions, and may importantly prevent detrimental information gaps about the cigarette industry. Future research should investigate the potential impact of increasing awareness of the MSA and cigarette industry practices in changing e-cigarette-related perceptions, which may help prevent e-cigarette use.