Researchers typically employ either peer or self-reports to assess involvement in bullying. In this study, we examined the merits of each method for the identification of child characteristics related to victimization and bullying others. Accordingly, we investigated the difference between these two methods with regard to their relationship with social adjustment (i.e., perceived popularity, likeability, and self-perceived social acceptance) and internalizing problems (i.e., anxiety, depression, and self-worth) in 1192 Dutch school children, aged 9 to 12. years. Perceived popularity and likeability were more strongly correlated with peer reports than self-reports, for both victimization and for bullying others. Self-perceived social acceptance correlated equally strong with peer and self- reports of victimization. Furthermore, peer reports of bullying were also correlated with self-perceived social acceptance, whereas self-reports of bullying were not. All internalizing problems showed stronger relations with self-reports than peer reports; although only the relation between self-reported victimization and internalizing problems was of practical significance. Despite our findings indicating that using only one type of report could be efficient for examining the relation between bullying behaviors and separate child characteristics, both types of report are necessary for a complete understanding of the personal and social well-being of the children involved. © 2012 Society for the Study of School Psychology.