The United States (U.S.) Food and Drug Administration has expressed concern about flavored e-cigarettes (e.g., JUUL brand) because they are appealing to youth who may be unaware that the product is addictive. The Population Assessment of Tobacco and Health Study Wave 3 provided data on flavor categories, type of e-cigarette product, and smoking status among past 30-day youth and adult e-cigarette users in the US. Most past 30-day youth and adult users reported using only one flavor category, with fruit (53% youth, 31% adult) being the most commonly reported category. Adults were far more likely to report using tobacco flavor alone, compared to any other individual flavor category or flavor category combinations (OR: 21.08, 95%CI: 5.92, 75.12). Whereas, youth were more likely to report using multiple flavor categories (OR: 2.03, 95%CI: 1.55, 2.65), with the most reported pairing being fruit and candy (36%). The variety of flavors on the market appeals to consumers of all ages. Although most past 30-day e-cigarette users reported only one flavor category, non-tobacco flavors were far more common among youth. Differences in flavor preferences among adult versus youth vapers may have implications for the role of flavors in both the initiation of youth vaping and adult vaping for smoking cessation.