To explain the cyberbullying with smartphones among college students in Korea, this study classifies the extant major causal processes with three factors of individual propensity, social environment, and opportunity each of which are extracted from three major theories of self-control, social learning and opportunity respectively. Furthermore, this study attempts to grasp both main effects and interaction effects among these selected theories, expecting that cyberbullying will be thoroughly explained when we consider the systematic and comprehensive composition of these main effects and interaction effects simultaneously. As a result of analyzing 301 college students in Seoul, Korea, the three major effects derived from individual propensity, social learning and opportunity are confirmed to exert significant effects upon cyberbullying. In addition, it is shown that all interaction effects between each two variables appeared to be statistically significant. However, the results including all interaction effects among major factors show that the interaction effect between low self-control and the perceived opportunity appeared to be statistically significant, while the other interaction effects among the rest of independent variables appeared to be statistically insignificant. Despite the limited effects of two-way interaction among included factors, we learned that we still need to consider both main effects and interaction effects simultaneously to thoroughly understand the subtle processes of cyberbullying in Korea.