Introduction: Rapid increase in youth use of Electronic Nicotine Delivery Systems (ENDS) led the state and the federal governments to implement minimum-age policies to restrict minors’ access to vaping products. Limited success of the age restrictions fueled efforts to increase the distribution age of all tobacco products to 21 (ie, Tobacco 21 or T21 policies). With limited data on the T21 policies, the current study examines the prevalence of ENDS use and the perceptions about ENDS among youth in the pre- and post-policy-implementation periods for one of these bans in the state of Florida. Methods: This study conducted secondary analysis on the responses from the 2014 and 2015 Florida Youth Tobacco Survey, which collected cross-sectional data. Results: Compared to the data from spring of 2014, the minimum-age policy enacted on July 1, 2014 did not lead to a significant decrease in Florida’s high school and middle school students’ ever ENDS use (14.9% in 2014 vs 25.8% in 2015) and current ENDS use (7.5% in 2014 vs 12.4% in 2015). There was some ambiguity among students regarding the ENDS harm—more students in 2015 thought of ENDS as both equally (11.0% vs 7.7%) and less (32.4% vs 28%) harmful than cigarettes. There was a decrease in the proportion of students who were unsure about their answer to this question (51.5% vs 59.2%). Conclusions: Policy change alone may not be effective in shifting the trend of ENDS use among middle and high school students. Although students may know about some of the ENDS effects, many of them are still not aware about the harms. Interventions in school and in the community should be aiming to raise this awareness.