Abstract This study explored the senior high school students' participation or non-participation in cyberbullying through the Semiotic Tradition of Communication Theory which views communication as an intersubjective mediation of signs and specifically using the Semiotic frame by Charles Sanders Pierce, which emphasizes the inter-relations between the sign or the signifier, an object (the signified) and an interpretant or interpretation. Eleven senior high school students who are digital natives participated in the study by engaging themselves in a conversation with the researcher. The participants of the study viewed the cyberspace as platforms for community building where friendships, alliances and sympathy are demonstrated in the course of interactions or communications. Also, the cyberspace is viewed as a platform for freedom of expression that allows them to express grievances about an issue and criticisms towards a person. These significations of the cyberspace intersubjectively mediated the students' participation or non-participation in cyberbullying. For those who did not participate in the cyberbullying incident, viewing the cyberspace as a platform where disrespect, aggression, immaturity, and thoughtlessness could manifest in the exercise of the freedom of expression mediated their action of nonparticipation. Also, interpretations that in the practice of freedom of expressions in the cyberspace, messages delivered could be seen by a vast audience where spread can be expansive hence ensuing a serious impact on the one bullied has interceded an act of non-participation in cyberbullying. However, interpreting the cyberspace as a platform where alliances are formed in their communications, and free expressions are expediently permitted has mediated participation in cyberbullying.