Bystanders in cyberaggression can support the victim, join the aggressor, or remain passive. We examined how supportive and passive adolescent Czech cyberbystanders (N = 443, ages 12-18) differ in terms of individual characteristics, emotional responses, and contextual factors. The most substantial distinguishing factor between the two groups turned out to be whether they had received a request to help the victim. After such a request, cyberbystanders supported the victim; moreover, most of those who had not been asked reported that they would have actively reacted to a request for help. The findings also showed the significant role of immediate empathic response, which increased the odds of support even after controlling for individual characteristics. The results are discussed with regard to prevention and intervention efforts.