Background Perceptions of health harms and addictiveness related to nicotine products, THC e-cigarettes, and e-cigarettes with other ingredients are an important predictor of use. This study examined differences in perceived harm and addiction across such products among adolescents, young adults, and adults. Methods We conducted a cross-sectional survey (N = 6,131, ages 13–40 years old) in which participants reported perceived harm and addictiveness for 11 products (cigarettes, disposable nicotine e-cigarettes, pod-based nicotine e-cigarettes, other nicotine e-cigarettes, THC e-cigarettes, e-cigarettes with other ingredients, nicotine pouches, nicotine lozenges, nicotine gums, nicotine tablets, nicotine toothpicks). We applied adjusted regression models and conducted pairwise comparisons between age groups (13–17, 18–20, 21–25, and 26–40) and product use status (never, ever, and past-30-day use), adjusting for gender, race/ethnicity, sexual orientation, and financial comfort. Results Overall, participants in younger age groups perceived products to be more harmful and addictive than those in older age groups, with the exception of e-cigarettes with other ingredients. For all products, participants who never used perceived each product to be more harmful than those who ever used. For all products, participants who used the products in the past 30-days had lower perceived harm and addictiveness compared to never and ever use. Certain sociodemographic groups, such as people who identify as LGBTQ+, Non-Hispanic Black, or Hispanic, had lower perceived harm and addictiveness for most products. Discussion Efforts should be made to educate all age groups and minoritized groups on harms and addictiveness of all nicotine products, THC e-cigarettes, and e-cigarettes with other ingredients.