This study examines the impact of low self-control and deviant peer affiliations on bullying perpetration and victimization in South Korea. Our sample is drawn from a five-wave, longitudinal study of 2,844 Korean adolescents (ages 11-15), compiled by the Korean Youth Panel Study. Theoretically driven models are tested using time-concurrent and time-lagged models to assess the time-ordered relationship between deviant peer affiliations and bullying perpetration and victimization, and latent growth curve models to assess developmental trajectories of bullying outcomes. Low self-control is incorporated as a time-invariant construct, and deviant peer affiliations is incorporated as a time-varying construct. The impact of covariates drawn from the mixed model is slightly different for bullying perpetrators and victims. The time-concurrent effect of deviant peer associations is stronger than the time-lagged effect on both bullying perpetration and victimization. Deviant peer affiliations fully mediate the link between low self-control and only bullying victimization in a full model.