Abstract Background Anxiety disorders are common during adolescence; therefore, detecting anxiety disorders among adolescents and providing appropriate treatment are crucial. Studies have suggested that watching online audiovisual broadcasts like mukbang and cookbang (hereafter mukbang), where hosts eat or cook food, may influence anxiety disorders. However, there is insufficient research on the association between watching mukbang and generalized anxiety disorder (GAD). Therefore, we investigated the association between watching mukbang and GAD among Korean adolescents. Methods We analyzed 51,764 adolescents who participated in the 2020 Korea Youth Risk Behavior Web-Based Survey (KYRBS). The participants were asked how frequently they watched mukbang per week over the past 12 months. Anxiety disorders were assessed using the generalized anxiety disorder-7 (GAD-7) questionnaire. A multiple logistic regression analysis was performed after adjusting for confounding variables. Results The prevalence of GAD was higher among adolescents who watched mukbang compared to those who did not (aOR: 1.100, 95% CI: 1.026–1.180, P = 0.008 in male participants; aOR: 1.090, 95% CI: 1.003–1.185, P = 0.042 in female participants). The frequency of watching mukbang showed a dose-dependent relationship with a greater likelihood of GAD in female adolescents. Conclusion This study’s results showed that watching mukbang is associated with GAD in Korean adolescents. Proper interventions for mental health are needed for adolescents who watch mukbang.