BACKGROUND Young adults new to tobacco (including e-cigarettes) are at an increased risk of e-cigarette use after e-cigarette exposure. This study examined the association between noticing e-cigarette advertising features and perceived product appeal among non-tobacco-using young adults. METHODS A sample of non-tobacco-using young adults (ages 18-29 years; n=1993) completed an online survey in 2021. We content analysed visible features from 12 e-cigarette ads that represented commonly used e-cigarette brands. Participants viewed the ads and clicked on the areas of the ads that drew their attention. Participants reported e-cigarette product appeal for each ad, including ad liking, product curiosity and use interest. We used generalised estimating equations to examine within-person associations between noticing specific ad features and reporting each and any type of product appeal, adjusting for noticing other features and participant characteristics. RESULTS Noticing people, discounts, non-tobacco (menthol and mint/fruit) flavours, positive experience claims or product images was positively associated with having any e-cigarette product appeal. Noticing discounts or mint/fruit flavours was also positively associated with e-cigarette use interest. In contrast, noticing nicotine warnings or smoking cessation claims was negatively associated with ad liking and product curiosity. CONCLUSIONS Attention to several e-cigarette ad features (eg, people, discounts, non-tobacco flavours) was associated with increased e-cigarette product appeal, whereas attention to nicotine warnings and smoking cessation claims was associated with reduced appeal among non-tobacco-using young adults. Restricting appeal-promoting features while strengthening the effects of nicotine warnings and smoker-targeted claims in e-cigarette ads may potentially reduce e-cigarettes' overall appeal among this priority population.