The purpose of the current study was to extensively investigate not only bystander roles but also individual bystanders' moral emotional responses in the context of cyberbullying based on the perpetrator's perceived popularity and the message type. Data from 566 adolescents in grade 7 attending six middle schools in South Korea were used to identify their bystander behavior and moral emotions in response to vignettes about cyber scenarios. Using latent profile analysis, the current study identified five types of bystanders: limited bystanders, pro-bullies, outsiders, defenders, and inconsistent bystanders. Moreover, multinomial logistic regressions were performed to determine the predictive power of the moral emotions of each bystander type. The findings indicated the importance of understanding bystanders' roles for designing effective intervention strategies regarding moral emotions, leading to adolescents' improved moral sensitivity.