Objectives An increasing number of US states have required a tax on electronic nicotine delivery systems (ENDS) in the past few years. This study evaluated the effect of statewide vaping product excise tax policy on ENDS use among young adults.

Methods We used the two recent waves (2014–2019) of the Tobacco Use Supplement to the Current Population Survey. A total of 17 896 US young adults were analysed. Difference-in-differences approach along with weighted multilevel logistic regressions was used to evaluate the association of vaping product excise tax policy adoption with current ENDS use, accounting for the clustering of respondents within the same states.

Results There was an increase in current ENDS use prevalence from 2014–2015 (3.4%) to 2018–2019 (5.4%). Respondents living in states with vaping product excise tax policy showed significantly lower increase in ENDS use prevalence during the study period (interaction between within-state changes and between-state differences: adjusted OR (AOR)=0.57, 95% CI=0.35 to 0.91), controlling for other state-level policies and sociodemographic characteristics. Additional stratified analysis with state-fixed effects by vaping product excise tax policy implementation status showed consistent findings.

Conclusions Our findings suggest that adopting a vaping product excise tax policy may help reduce ENDS use and suppress the increase of ENDS use prevalence among young adults. Considering that there are still a number of US states that have not implemented vaping product excise tax policy, wider adoption of such policy across the nation would likely help mitigate ENDS use prevalence.