This paper examines factors correlated with online self-help—an informal form of social control vis-à-vis intervention—upon witnessing a cyberhate attack. Using online surveys from 18- to 26-year-old respondents in the United States, we explore the roles of various types of online and offline formal and informal social control mechanisms on the enactment of self-help through the use of descriptive statistics and ordinal logistic regression. The results of the multivariate analyses indicate that online collective efficacy is positively related to self-help, as is having close ties to individuals and groups offline and online. Formal online social control, however, is not significantly related to engaging in self-help. Other findings demonstrate that personal encounters with cyberhate affect the likelihood that an individual will intervene when witnessing an attack, and that individuals with high levels of empathy are more likely to intervene to assist others. This work indicates that pro-social online behavior is contagious and can potentially foster online spaces in which harmful behaviors, such as propagating cyberhate, are not condoned.