All of us cannot imagine adolescents' daily communication without humor and making fun of each other. Jokes can help strengthen friendships, smooth out the awkwardness, or maintain status in the group, but sometimes jokes become a means of humiliation and bullying. Despite many studies, determining the demarcation line between comic and aggressive words is quite challenging. This border remains uncertain. This paper aims to identify characteristics in which a joke becomes offensive and can develop into bullying.The article presents the results of a qualitative analysis of 72 interviews with middle and high school students. We identify three situations when a joke is perceived as aggression. Firstly, If a fun statement emphasizes the differences between the adolescent and the group, it makes one feel "inferior" compared to peers. Secondly, the difference in statuses between a speaker and an interlocutor exists, leading to no reply to a joke using a joke. In that case, the joke ceases to be a part of the dialogue and becomes a means of reinforcing inequality. Thirdly, if not all participants are aware of "the rules of the game," they cannot understand the context of reading the joke. That means the statement is interpreted in different ways by the parties, leading to resentment. The findings can help design effective bullying prevention measures in the school environment.