This article examines characteristics of online harassment episodes associated with increased distress for youth. Data were collected as part of the Third Youth Internet Safety Survey, a cross-sectional telephone survey conducted in the United States in 2010. Interviews were conducted with 1,560 Internet-using youth, ages 10 through 17. Harassment incidents involving multiple perpetrators, offline contact, and a power imbalance between victim and perpetrator were more likely to be upsetting to youth. As the number of aggravating features (i.e., multiple perpetrators, offline contact, power imbalance, repetition) that an incident included increased, the likelihood of distress also increased. Findings have important implications for schools and parents seeking to improve prevention and intervention efforts.