Background: The prevalence of allergic rhinitis in South Korean adolescents is increasing. Adolescents in South Korea currently use liquid electronic cigarettes more than heated tobacco products. Objectives: The purpose of this study was to assess the association between the use of liquid electronic cigarettes and allergic rhinitis diagnoses among South Korean adolescents. Methods: This study used data from the 17th Korea Youth Risk Behavior Survey in 2021. Out of a total of 59,066 students, data from 18,869 students who had experience with liquid electronic cigarettes were used in the final analyses. Diagnoses of allergic rhinitis by medical doctors were self-reported as outcome variables. Results: For females, when comparing ‘daily users’ and ‘current users’ with ‘never users’, the adjusted odds ratios (ORs) for ‘allergic rhinitis’ were 2.20 (95% confidence interval (CI), 1.00~4.84) and 1.49 (95% CI, 1.07~2.09), respectively. For males, when comparing ‘daily users’ and ‘current users’ with ‘never users’, the adjusted ORs for ‘allergic rhinitis’ were 1.42 (95% confidence interval (CI), 0.91~2.22) and 1.41 (95% CI, 1.08~1.84), respectively. Conclusions: The use of liquid electronic cigarettes was statistically significantly associated with increased odds of allergic rhinitis, especially for females. The results of this study will provide a useful scientific basis for establishing public health policy and using the educational data related to the use of liquid electronic cigarettes in the future.