<p>Cyberbullying is a public health issue that continues to concern both the public and research spheres. As the use of social media platforms becomes more rampant, so does the risk of being impacted by cyberbullying. While it seems clear that cyberbullying might vary across social media platforms, limited research has examined how and why it varies. A better understanding of this variation can help in designing policies that are targeted toward minimizing cyberbullying and the resulting negative mental health impacts. The present study explored variations in cyberbullying across social media platforms by conducting 35 semi-structured interviews and three focus groups with college students from a university in the southeastern United States (US). All participants had either experienced or witnessed cyberbullying. Through thematic analysis of the interview and focus group data, the research team developed six themes that capture how and why cyberbullying varies both across and within social media platforms. The themes include (1) the level of anonymity, (2) the publicity of the posts, (3) the user profile, (4) community culture, (5) the purpose and format of the posts, and (6) the level and type of regulation. The themes highlight important features of social media platforms that can either facilitate or inhibit cyberbullying. Practice and policy implications of the findings are discussed.</p>