Cyberbullying bystander behavior has attracted increasing attention and research over the past decade. Nevertheless, less is known about the applicability of traditional criminological theories in explaining bystander response patterns to cyberbullying. Additionally, the study examines gender differences in the relationship between self-control and cyberbullying bystander behavior. The sample comprised 501 adolescents, age 14-18 years, in Israel. The findings partially support the general theory of crime and show that various measures of self-control (impulsivity, risk-taking, self-centeredness and physical activities) significantly predict cyberbullying bystander online behavior. Furthermore, the study found that the relationship between self-control and cyberbullying bystander online behavior differs by gender. While impulsivity was significantly related to adolescent boy bully-supporters, adolescent girls who supported the cyberbully were characterized by self-centeredness and risk-taking. Moreover, physical activities as a measure of self-control was found to be a significant predictor of adolescent boy bully-supporters and of both adolescent boy and girl victim-defenders. The discussion focuses on the theoretical and practical implications of these findings and suggests directions for future research in this area.