Background: In South Korea, there was an 80% increase in tobacco cigarette price as of January 1, 2015. At the same time, electronic cigarette (e-cigarette) use among youth was a serious public health concern in South Korea due to exploding use. This study examined the association between cigarette smoking behavior changes after such a cigarette price hike and e-cigarette use among Korean youth. Methods: A nationally representative sample of 11,628 secondary school students who ever smoked were drawn from the 2015 Korean Youth Risk Behavior Web-based Survey (KYRBS). Of the 68,043 students from the original 2015 KYRBS data, 56,415 students who never smoked a cigarette in their entire life were excluded. Current e-cigarette users were defined as students who used e-cigarettes at least one time in the past 30 days. We classified participants into three groups based upon changes in cigarette smoking behavior after the cigarette price increase as quitters, curtailers, and others. Multiple logistic regression analysis was conducted to estimate the likelihood of e-cigarette use. Results: Overall, 20.8% of the participants who ever smoked were current e-cigarette users in 2015. 17.1% of the participants reported quitting or reducing the number of tobacco cigarettes after the cigarette price increase. Of the quitters or curtailers, 33.7% were current e-cigarettes users. Quitters (adjusted odds ratio [AOR]=1.33, 95% confidence interval [CI]=1.04-1.71) and curtailers (AOR=1.24, 95% CI=1.07-1.42) were more likely to use e-cigarettes than their counterparts. Conclusions: Smoking behavior changes, specifically quitting and reducing the number of tobacco cigarettes after the cigarette price increase was associated with increased e-cigarette use among middle and high school students in South Korea. School health professionals should provide effective interventions and education sessions for tobacco use prevention and cessation especially for those who switch from tobacco cigarettes to e-cigarette use.